Hello everybody.

This is a bonus lecture.

And we are going to talk about amplifiers.

So this week is a Valentine's Day week here in the United States of America.

So there's a lot of countries I guess that have this holiday.

It's basically a holiday for you know your girlfriend or your wife.

Anyway so if you are in the United States or a country that celebrates it.

Do not forget.

For me it's fun because I have a little daughter so I took her to a daddy daughter dance and I'll take

her to another one.

So that's kind of a fun thing to do if you have a little daughters on Valentine's Day good little dances

anyway.

So you know I've been trying.

Normally I would have put out a bonus video a couple of weeks ago but I've been really trying to think

of something useful and interesting.

And again we you know we only have an hour to do it and so what I was thinking is a lot of people have

been asking me about amplifiers and so I thought it would be maybe a fun project just to build an amplifier

in real time as you can see the thought process and the steps that we go through.

All right.

So that's what we're gonna do we're gonna build an amplifier.

Now we're not can build anything crazy in one hour we're going to build a very very very very simple

amplifier but I'm going to talk to you about my thought process some of the things that you're thinking

about so that you could build more complex amplifiers.

All right.

So let's just dive right into this.

So let's say that you you know you build some project and it hasn't maybe an audio output right but

the audio output does not have any power so now let's talk about this for a minute what this means by

power.

Now if you're watching a bonus video you could have skipped the entire course and just watching this

bonus video so obviously if you take the Clash you're going to know a lot of these things and I'm talking

about.

But when you're talking about amplification there's three kinds of amplification we can amplify voltage

we can amplify current.

We can amplify both which would be a power amplifier.

So when you're doing a audio amplifier typically we want to definitely amplify power and many times

you want to also amplify voltage.

Now a lot of times you may not need to amplify voltage for example say if you have a five alarm system

or even a three point three volt system and you generate an audio output that audio output is already

going to be swinging five volts or three point three volts.

Most of the time that's enough to drive a speaker no problem.

The problem is there's no current to that drive.

Right.

So you've got the voltage but no current.

So you need more current.

So that's where the power amplification comes in with the audio amplifier.

Now many audio amplifiers also have voltage amplification so you can take a tiny signal maybe a midlevel

level signal and amplify it 10 50 100 times.

So those are some of the things that you're looking for an amplification you definitely want power amplification

meaning I want to amplify current and potentially also voltage but I definitely need current because

we want to put out Watts or fractions Watts or many watts when we're talking about amplifiers right

audio amplifiers.

So a typical audio amplifier something in a small handheld device like say you know like this phone

maybe this little speaker puts out oh maybe 500 Miller Watts right 200 500 million watts.

I doubt it puts out a what.

All right.

And then you'll see these big giant stereo systems maybe puts out 500 watts or a thousand watts you

know maybe at a concert crazy big stuff right.

All right now.

So then we say OK hey we want to build an amplifier and then you could go look and you could say you

know what are some amplifiers it'll break out boards so that you can play with using experiments.

If you go to Amazon and type an audio amplifier breakout board we go through here and you can see there's

various small devices here and kind of look through them and you can see what's going on here.

So for example we look at some of these that came up in the first search.

Some of those are fairly complicated like you can see this is a very nice one but some of the simpler

ones like this right here come in here and we see OK.

So a one point four watts and domes what that means is it can drive one point four watts of power into

an eight ohm load or an atom speaker.

Right.

And then if you look at it it's just basically one chip and then this is a potentially a regulator I'm

not sure let's get another view here.

And so very very simple and we can see it's based on this particular I see this TPA 2005 D1 which I

know is a Texas Instruments amplifier so we could go look this I see up and say let's take a look at

this and just basically copy something like that so we can do that and we might do that right.

Again I'm doing this in real time with you right now as we do it.

Now here's another one.

This is now this is shockingly expensive actually.

And this is based on this.

Pam 83 02 2.5 watt single channel Class D audio amplifier.

So this class D.

If you don't know anything about amplifiers then you're going to be like What does that even mean.

Even if you know about amplifiers you may not be familiar with D for digital.

And we're going to talk about that also but for now we're just we're shopping we're just you know looking

around and so this spam 83 02 I I've used these Pam chips before.

This is from.

I'm trying to remember what company makes these Pam chips.

It is let's see here.

It's is a diodes Inc.

Yeah yeah it's diodes zinc.

So the company diodes Inc.

They have a whole line of these audio processors or audio amplifiers that start with PJM which I don't

know what the PM stands for but anyway they have some really good ones that are fairly simple.

And so this is a good company to get simple amplifiers from now Texas Instruments and Maxim I have a

whole line a whole slew of amplifiers like I don't know dozens maybe even over 100 diode zinc does not

have that many but they have some simpler ones that are easier to get up and running.

All right.

So we want things that are fairly simple so there's another possibility the eighty three or two a is

a 2.5 watt class city.

So there's another possible opportunity for something that we might want to use.

All right.

Let's go back here.

So we saw you know there's this panel I see.

And this tie.

I see.

Let's see what else is this thing right here is more complicated this I think is a audio file file playback.

I see there is another Pam 83 02 now at eighty eighty four O three and a lot of times when you see these

numbers increase it might mean it's stereo.

I mean it's more power etc. that's all.

And another thing that you can kind of glean from this is what manufacturers make eye sees and then

what are people using to make these little kids because they went through the same process we So like

here here's another TPA 31 16 to buy 50 watts.

Now this one's interesting because this is a very high output amplifier.

So it's two channels by 50 watts Class D.

That's a big powerful amplifier right.

That's no joke right there.

So someone has to go through this process now the process of looking for these things is a very time

consuming when you go to the manufacturer Web sites.

All right.

Let's see another pan eighty three or two and there's a two thousand five again.

So now what I want to show you is so you could go on Amazon and you could look this up.

You could also go to spark fun which is another site and I'm trying to keep healthy on the time here

because we do not have a lot of it audio amp.

Let's see what comes up here.

Audio amplifier and come on Spark fun and render the page.

So there is one with the 2005 that we just saw.

Let's see here.

Anything else exciting and.

OK.

Here's one here.

Oh this one's I squared.

S All right.

So now you can either drive these amplifiers with an analog signal which is kind of what you would be

used to or I Squared US and my course is not a digital course it's a basic electronics course and PCV

design.

But I talk about I scored us a little bit I Squared US as a serial protocol similar to I squared C and

these things stand for Inter I c communications I swear at C and I squared S's inter I c sound I think

it's a sound version of Ice squirt C basically so you can digitally sound send information to and I

C and amplify it so that you aren't working with analog signals that can degrade you're working with

digital representations.

So this is nice if you want to do an eye squared s amplifier and if you have a microcontroller or a

computer or something that has a nice grid US output well we're not going to do that.

Nevertheless Max member I said Maxim semiconductor has a lot of audio amps and this is one of them right

here that's 9 8 3 5 7.

So anyway let's go back and then of course eight of fruit is another great website that has a lot of

cool stuff.

And if we look under audio amp here and then there's a there's quite a few of them actually.

And so again this is a great way so there's a TPA 2016 and this one's got ice squirts sea control.

So that means that you need a nice squirt sea bass to control it and set the registers in assets.

That's a little bit more complicated than we want to deal with.

So this Pam 83 o to say this Pam series is you know looking good.

And then here's how that I squared asks you don't want to mess with that.

And then there's 14 pages it probably degrades it to other things that are not the search terms.

Here's one.

This one is two by three point seven and this is this Max 9 8 3 0 6.

And then here's this Max 9 7 4 4.

Let's take a look at this one.

Take a look at this one right here.

All right.

So 9 7 4 4 for example kind of we can look here at it.

So this is a fairly complicated chip.

He has a you know a good amount of support hardware around it.

A lot of stuff.

And we we may not want to get that complicated to do whatever we're going to do.

But again we're just kind of looking and getting an idea now.

So we want to make an audio and finally say Hey Andre why not just use an L M 386.

Right you may have heard of this we could do this but I mean these Elam 3D sixes are very very very

old.

Now even though this says 2004 this thing is predates this.

So this is kind of a very crude audio amplifier.

I see there a buck there real simple to use.

They have a wide supply voltage range.

So and here is what the circuit looks like inside of an L M 386.

So you could just make something out of this.

It's got an input couple other pins here.

The output ground power supply and then it's also got you can set the gain in this a little bit.

And if we go down here and look down here consumed it looks like minus plus ground game game bypass

these different inputs and we can look at some of the circuits of this there's kind of this functional

diagram.

Here's an example circuit.

So you can see with the L M 386 for example you can make a you know a good audio amplifier and the input

comes here and then this is kind of a volume control control using this potential emitter as a volume

control the not inverting input is grounded.

And then some of these other friends do other things like set gain and whatnot.

The one big problem with using an L M 386 is it needs an AC coupled output and you need a very large

output capacitor usually 100 200 300 micro adds to block DC so that only the AC single gets through

here and you went like very low frequencies like 10 hertz and up so you have to put a big capacitor

here and a lot of people don't want to put a big capacitor that's a big part especially for making a

surface mount a board.

Nevertheless the L and a 386 is surely not bad and you could always make an amplifier out of this.

This is specifically designed for amplifiers.

The elem 36 and amplification circuits.

And here's another example with game 200.

And again this is voltage gain two hundred.

So the voltage gain is two hundred.

Then the final output right will be whatever that voltage is through whatever this impedance is.

And this impedance is a speaker that will draw as much current as it needs so that the final output

will be the voltage times the current obviously.

Right.

Okay.

And just some more some examples setting gain with these games settings I believe in 1 and pin 8 help

set gain anyway the datasheet on this is not short and I think it's about let's see does this yeah.

Twenty nine pages.

Twenty nine thirty pages.

So you could use an alum 36.

Now another thing that you could do if you want to make an audio amplifiers you could use an op amp

right.

No one said you can't just use an option.

And again I'm showing you know parts that are very common in kind of older because they're ubiquitous.

So the elem 741 is kind of a very very basic operational amplifier.

I would never ever use any product or project I ever made professionally because it's just too slow

too old too.

Everything everything now is a thousand times better than this on every single factor power noise amplification

linearity I could go on and on but it's simple and this is kind of you know if you start learning about

electronics and you want an operational amplifier hey people say using alarm seven forty one just like

for transistors I'll tell use it 39 for third nano 6 2 2 2 2 A et cetera in the course same thing here

and we don't talk about operational amplifiers in the course other than a little couple anecdotal things

where we talk about and just for a few minutes but operational amplifiers are basically black boxes

that are idealized amplifiers and you can set them up in different ways to kind of create all kinds

of different amplification and functional analog operations amplification is one of them.

This configuration right here is a non inverting amplifier configuration with it there's countless configurations

that have different properties and they're really cool properties there are whole books thousands hundreds

hundreds of books on operational amplifiers and if you just google for operational amplifier circuits

there's tons of them you can find PDX from Texas Instruments and other companies that make really good

white papers that are hundreds of pages long describing how to do circuits with op amps.

So we could you choose an option.

There's no reason we could just do that.

All right.

But again when we do things ourself then we have to understand what we're doing so we have to understand

things like filtering and and power amplification and so forth.

So in this case we just kind of want to use a chip.

Right.

All right.

So you just want to use a chip.

OK now let's go a little bit farther.

So now we want to use the chip.

So we go to a place like Dickey and I've typed in audio amplifiers here and I think yeah.

Fifty nine hundred.

All right.

So then we can go through here and we can say OK you know where do you even begin.

Right OK.

There's a lot of these different parameters here.

The first thing is before we do anything we need to understand what we're looking for.

All right.

So let's first let's say I want audio amplifiers and stock.

I want it rowhouse bulk or cut tape.

OK.

I don't want to care about the series I want it to be active.

This type thing we don't understand this yet.

I'm going to talk to you about this in a minute.

All right.

So let's go there and now supply filters.

All right.

Give that a second OK.

Then we have Max power output.

We're not complete with that yet.

We're not going to play with voltage supply all that yet.

But I do want it to be a surface mount Chip.

OK.

So surface mount surprising there's not that many through hole.

There's almost no through hole.

OK now it's seeing the output type.

All right.

And we can say one channel one channel to channel stereo can say to channel cereal all these different

variations.

So we kind of need to know what matters here to us.

All right.

Before we go do that let's go talk about the class of amplifier.

Let's go talk about the class of amplifier.

So I think I have something open here.

Yeah.

All right.

So when you're talking about amplifier class there are many many classes now there.

And here's a little chart you can see there's a there's a b there's B there C and then there's you know

DCF g h i t there's all these other classes which have just kind of happened recently in the digital

world to describe those kind of classes.

But what I'm going to talk about is these simple these simple amplifier classes so an amplifier amplifies

the entire signal.

All right a amplifier amplifies the entire signal it's very linear and I think there's a circuit of

it here.

Yeah.

So again if you don't if you haven't taken the course I can understand it's too much but in this case

we bring the signal in here we capacitive couple it and then this transistor is biased into the operating.

It's operating right so it's bias it's running and then we take a small signal and then we get out a

larger signal here.

So the transistor is always on.

So here's the input and here's the output.

So we get an amplified version of the signal.

The transistor is always on.

So even when there's no signal in here on the input the transistors still running it's running hot burning

energy.

Right.

This gives you a very linear great amplifier but it burns a lot of energy.

So if you want an amplifier that gives you the best audio right then a lot of people just stick with

a class say and they'll just burn energy now.

So then we said hey let's come up with another one and let's let's see if we can you know reduce this

power so then there's these other two classes or this a B and B classroom.

Now if we come down here take a look here.

So we have this class B amplifier so then the class B amplifier how it works is there are two transistors.

So one transistor turns on when you have a positive going signal.

The other transistor turns on when you have a negative going signal.

All right.

So what's happening here is when you have the input signal come in you get your output signal.

And this isn't showing the entire signal you get your output signal which is turning on each one of

these transistors depending on which wave or which half wave of the input.

All right.

The problem with this is the problem with this is is that as these things turn on all right they need

to there's a portion where they turn on so you get kind of this discontinuity at the at the middle point.

So in other words as the signal goes up and goes down there's a little amount of voltage that gets lost

turning on each one of these transistors until you start getting amplification.

All right.

So you get this non linearity All right.

So then we kind of mix these two things and then there's this a B.

So what a b does is it it overlaps the on portion.

All right.

So wait a little bit of energy.

So if you go to a B here is hopefully there's a B.

So in a b what we do is is we bias these transistors in such a way that we turn them on so that as these

transistors are conducting and they're making this crossover point there's a crossover there's an overlap

so that we get the signal out but we don't get those discontinuity so we get a better linearity in the

end the output signal.

All right.

And what that does is it burns a little bit of energy but for it we gain a better signal so the bottom

line is is that if we're looking for transistor amplifiers we are interested in an A or an A B.

We don't we're not interested and B we're not interested in C and then over here these digital amplifiers

take a look at those.

So now we can convert the signals the chips can convert the signals into a pure digital signal if they

do that they start off the first ones a D.

And if I come down here where are we.

Yeah.

So here's where it starts to talk about this.

So a Class A D amplifier is basically a nonlinear switching amplifier EPW an amplifier.

All right.

And then and then from that it there's all kinds of variants of it f G I.

All these different things which are more or less fairly arbitrary they just kind of started coming

up with these as companies invented these things.

But the bottom line is these are all digital versions of analog amplifiers.

So you can read through here like a d amplifier is basically this P.W. impulse with modulation amplifier.

So it's completely in a digital domain.

All right.

And they can you know theoretically reach a hundred percent efficiently and then Class F both efficiency

and output using harmonic resonance.

You know there's all these kind of crazy things that they try to get better performance lower power.

All right.

So what we're looking for is either A a B or if it's a digital amplifier we'll go for a D.

Now that digital doesn't mean that it necessarily will take a digital signal.

It just means that internally it converts the signal into a digital signal amplifies it and then converts

it back into an analogue signal using this technique for the output and that's why it's called The Class

D or add for G or whatever amplifier.

All right.

So that's the type of amplifier.

OK.

So given that let's go back to our search so we like a we like B.

All right.

And then in fact we like all these all these will do.

All right.

Notice is no B and there's no C right.

No one wants those.

OK.

Let's go hopes clear that.

All right.

And then we we've already applied our filters do that again just for kicks.

OK now we're going to talk about do we want to amplify headphones you do we want to amplify just speakers

kind of thing.

Right.

And do we want to single model or stereo.

All right.

So let's go ahead.

Let's make this stereo.

All right so we want to channel stereo and this is one model or two channel Sierra 1 my model with mono

headphones and stereo headphones all this different kind of thing.

I just sort of stick to two channel Stereo.

All right.

And in fact and I don't even want headphones let's not mess with that.

Let's just go to channel stereo done apply filters

all right here we go.

Now let's go and sort by price.

You know I'm always concerned about price all right.

Now let's see what we came through here.

Oh look at that.

Check that out there is that Pam 84 oh three came up right there is a Pam eighty 06.

Here's an interesting chip.

So this is a B to channel two point two to five volts.

Sixty eight cents it's pretty cheap.

And does it say what though.

It doesn't say what the wattage is.

Let's go take a look.

This one right here this in C on semiconductor and then of course like I said the big you know the big

companies will have tons of these kinds of chips but you'll you'll see outliers from other companies

that have a few ices piece of advice.

If you're building and designing a product where you building millions of something.

Be careful if you find some you know company that now on semiconductors a very large company but maybe

they're their core strength isn't audio amplifiers maybe they got just one or two.

Right.

But they've got 50000 of some other kind of chips that they design.

I'm I feel good about buying one of those other chips right.

But if they've only got a couple audio amplifiers it's not really important to them long term.

The roadmap long term so I really don't want to buy those chips because if I go build a product with

one hundred thousand ten thousand a million 10 million hundred million units right ideally hopefully

I don't want to be stuck with a company that's like we're not into this anymore I'm not going to build

this chip anymore.

So be careful.

Pick chips that you can find a lot of and it's a core strength of the particular company.

OK.

All right.

So this whatever this is here let's go take a look this datasheet see we're doing here and this is what

I do.

This is the process right.

And I want you to see this.

So no cap right.

So this has something to do with no capacitors I would imagine I probably seen this chip before but

I've never uses pop free it just means it doesn't pop make popping sounds when there's transitions in

the audio when the audio turns on turns off a lot of audio amplifiers will pop and click.

It's very annoying.

All right.

So it says from 20 hertz to 20 kilohertz is the flat frequency response meaning from 20 to 20 kilohertz

it will amplify the same way and doesn't have a frequency dependent amplification which of course you

don't want in a amplifier.

It works some two point two to five volts.

OK so that looks good.

This PSR this is the power supply rejection ratio 90 decibels which means that is the power supply is

all over the place.

The audio will not hear it and adjustable game from one volt to Volt to ten multiple.

So all this means is basically one to 10 for the voltage gain.

All right.

And there it is looks pretty simple.

So this is not bad.

Let's see if there is a schematic.

I like looking at schematics because that kind of shows you what they think you're supposed to do with

the chip and some equations here resistor divider probably for gain or something.

This is a this is for shut down book.

That's something else.

All right.

And yeah.

So as you can see.

So this this basically is a very simplistic amplifier.

So here's a differential mode version of it and here's a inverting configuration using it.

So it's basically like an op amp it's a very specific kind of APM so that's what this thing is it's

like an op ed but you can see it even as a symbol of an option.

So this is a it's like the elem 386 that we're looking at or the 741 the alarm 741 it's just kind of

an op ed.

All right.

So that's a possibility we could use up but I want to be a little bit more like a black box an audio

amplifier.

Let's move on.

All right let's see here.

We've got this Pam.

Eighty four or three.

Now we saw that there was at 84 0 2 I believe was the other one.

So this might be interesting.

I don't wanna mess with anything that's a BPA ball great array.

I consider but a lot of people won't be able to.

So we're gonna do this surface melt so this eighty four or through this take a look at this one.

All right.

This is three what.

This doesn't look too bad.

See we're doing here and this is you know and if you watch the videos and you know how I do this this

is a painstaking process of figuring out what to put into things.

We're just we're sitting here looking at some basic chips if we were doing this professionally I might

have to give you 100 200 300 I meaning I got to look at 200 300 data sheets then I might pick 10 of

them that I like then I might have to get 10 samples and I might have to build 10 boards or get 10 dev

kits and listen to it look at its performance.

All of that could take hundreds of hours just for one ship that I'm going to put into a final design

and a final design might have 10 50 100 chips right.

So this is a long process but this is how it's properly done.

So you just not picking random things that other people pick like we can go on Amazon look what someone

else did.

But here's the process where we're doing it ourself right.

Okay.

So if we look at the design here.

So now you can see this is a little bit more of a black box.

So one thing is we've got a couple power supplies here we have to look here because it might require

two different power supplies that would be bad which is more complicated for a little board but here

this input left input right.

Zoom in a little bit.

Input left input right.

These are capacitive Li couple through small capacitors point for seven I can deal with that.

This has got.

Now here's an interesting look up here.

So here on this Peavy D.D. 470 micro freighters of the recommended bypass capacitor.

Why is it so big.

Well I'll tell you why audio amplifiers are going to pull an enormous amount of current right now.

We saw the other thing where we had the capacitors and the output to the Speaker.

Those were for filtering on the L M 386.

We don't like that but we don't mind if there's big bypass capacitors here and they're just required

because when you pull so much current you need to get it from someplace if you run back to the power

supply over the impedance of the of the lines to the power supply you're going to get a voltage drop.

So you put a big capacitor at the chip a hundred microfiber to hear my crowd for a microphone or a thousand

microphone out so that you can get that current that charge that you need.

So this is very common.

All right.

Anyway you've got to shut down pin a mute pin a bunch of grounds and then we basically get these two

out.

But so this looks to me like a very simple I see and input left input right stereo and put these a reference

to ground.

All right.

I don't see a gain control.

Don't see.

Gain control.

So if we back out here and we see your internal reference connected bypass capacitor mute.

These are just digital lines.

Mute active low and then shut down just shuts the whole thing down for power active low.

All right.

And see if there's anything else interesting here.

But your charts again I would read this very carefully.

Kind of here's a block diagram of there.

What you we call it operating voltage just 5.5 and the PEM 80 for us for it.

Should we notice that the voltage of four new dry.

Okay.

So this is battery works with LCD should be connected for it's powered on.

All right.

And so this is talking about here's like the whatever their output is and they've got a filtering system

on it also just to filter some of the stuff we don't care too much about that.

Let's see here.

Let's see maximum gain as shown in the block diagram.

The eighty four threats to internal amplifier stages the first stage gain is externally configurable

while the second stage is internally fixed.

The closed loop gain of the first stage is set by selected ratio of RF to our eye while the second stage

game is fixed at two times.

OK.

So we can't play with those two times so we can play with this.

All right.

But my question is where is this RF and I.

Which usually is feedback and input.

So let's go back to the design here.

The little schematic that they did.

So here here let me zoom this a little bit for you.

So here is this.

I that you're talking about so this is this is our input.

So then this r f we kind of need to figure out where that RF is.

Right.

Where's that RF.

So that's where the gain is getting set.

So I can sit here.

Let's search for RF and

picking up just words here.

All right.

Plus selecting the ratio of our after all right.

This is going to show you the average gain but we still know where this RF is in the actual design.

So sets a maximum half of 142 a minimum of 18.

OK.

So that tells us the range that we can select here.

That's great.

But we still don't know where we put this RF.

How is it getting this.

This is showing some filtering that you might want to add if you're having noise problems.

So on this right here I like this but I'm not clear where the feedback resistor is on each of these

channels.

All right.

And here's the input here's the input and this is actually.

So see this right here.

These are feedback resistors.

This one and this one.

There's two stages this one in this one.

See this attenuation decoder.

And this is connected here that's connected here mute but I don't see how to set it so we'd have to

figure that out.

Right.

And this is why this stuff takes time.

Right.

Ready 30 minutes and so we've got to move on.

OK.

So that's a possibility this Pam.

Pam I see OK.

All right.

Let's skip through the Pam things we've kind of looked at the Pammy stuff and so this 80 so I've looked

at this 80 for 0 6 before what were we just looking at.

We were looking at an 80 4 0 3 84 0 6.

Now this is class D and A B.

This is to channel 5 what times 2.

Let's take a look at this one.

So I've looked at this at some point and let's see why I liked it is this anything.

OK so the Pam A4 0 6 offer is low to HD.

That's a stance for total harmonic distortion and that is a measure of noise between harmonics during

the amplification and you know all you know all these different ships depending on what you're doing

have a whole language of their own that you have to learn what all these acronyms mean and and so forth

so you can't know everything.

So you got to read through this.

So five watts to them load three watts at a forum load.

Okay so this looks fine.

Now let's go over here so we set a block diagram.

Roy's in the block diagram.

Now if you look at this high and low so this is interesting.

So this allows us on this mode switch to put it in high which is class D digital or low which is class

A B it's stereo output.

Notice on this one they use much smaller bypassed capacitors and then again there's this r n and we're

not sure about this whole game thing.

So let's just search for gain

and RL

And let's see let's see.

So works in D should be connected one should not mix so this is very similar to the other one and we're

not quite sure we're not quite the palm sets maximum traffic was what minimum R equals this.

So the closed loop game is twenty four.

I'm not sure if it set itself or if we set this RF It doesn't look like we do.

So again you know I'm already confused by it's a little bit of this chip and maybe I don't want to figure

this out right.

So let's keep going.

OK.

ISIS SSI is as a good company but they don't make a whole lot of amplifiers.

All right.

We can look at this two point six.

And again you just got to go through this and this is a huge pain right.

And then down here to the.

Now we're starting to get a little bit more expensive.

Now this one new.

So to channel stereo two point forty five class A B.

Let's take a look at this Max for forty sixty two chip

OK.

All right.

So this is interesting.

So this one right here.

This looks like it's a microphone amplifier differential microphone.

Yeah it's a microphone amplifier.

OK.

So that's cool.

Fine whatever the search came up with something that we weren't interested in.

All right.

And then here's some of these TPA chips.

Now notice it's got you know a good amount of pins here.

Now if you're afraid of a lot of pins on a surface mount you know we can avoid that.

So maybe let's go take a look at this uh DRP I've actually this Chip I'm familiar with.

Also let's take a look at where did it go this for.

This one does look too bad this elem 4 6 6 6.

Class D to channel one point to what not a whole lot of wattage there though.

Let's take a look at

OK

OK the alarm 4 6 6 6 is a fully integrated single supply high efficiency switching audio amplifier it

features an innovative module modulator that eliminates the LC output filter typical switching amplifiers.

We talked about that you might have to filter the output if it's a switching amplifier.

OK fine.

And again you'd really want to read through this.

OK so what do we got here.

So here's the right.

Right.

Input and left input.

So this is showing differential inputs but we can ground one of these if we wish.

And we've got right we've got left and it's got kind of a little gain control here.

So this doesn't look too bad or ISIS doesn't look too bad.

All right.

So let's take a little bit look here more and scroll down here a little bit if the browser will cooperate

with us

okay.

And what I again I'm looking for just kind of a schematic here.

So here's the single ended input version that we we're going to kind of use.

Right.

And so it's very very very very simple.

All right.

So I'm liking this and this looks pretty good.

And notice its capacity release outputs on the speaker output so that's cool.

All right.

And a very simple network here just basically we've got it.

The power comes in.

It's bypassed and then it's split on these two supplies and then bypassed again.

We can do that and improve that a little bit.

And here is if you want to add a little bit of more flair to it and put these these filters so these

are these are filters here and then this is also from making measurements.

And then this stuff right here is a jumper so you can kind of short these inputs and then a switch so

you can select to gain select and so forth.

We're going to look at that gain select in a minute and see how that works.

And then this is basically showing the delicate schematic all right.

And PSB layout and that's about it.

Okay.

So you know what.

That's not bad.

It's only one point two watts which is a little bit thin.

I'd like it to be a little bit higher but elem 4 6 6 6.

Not bad.

ELAM four six six.

It's you know it's a buck fifty so it's fairly simple.

So I kind of like that.

And what do we have over here.

Now here's another one and this is LME 1877 and elem for eight 325.

Let's take a look.

Let's take a look at this one this one school was got 20 pins.

Let's look at this one.

This Elm 1877 see what this is talking about.

If we like this all right.

This is looking a little bit old school.

Nineteen ninety five I can tell it's a little bit old to ask for Channel.

All right.

And OK they show the inside of it.

Great.

And let's look at the schematics.

This is fairly old and again this is.

Yeah it's since basically these are op amps in here.

Right.

These are off amps in here.

It's kind of showing you different configurations Nat.

Not interested not interested.

Let's back off that.

All right we got about about 20 minutes more so we want to find a chip so we can do a design.

All right.

And let's see this elem 48 80 direct path.

This D.R. V.

Let's take a look.

This one this 40 80.

All right.

It's got very few pins so it's not gonna have a lot of features.

I can tell you that and this is going to probably just be two under 50 mil twat.

Yeah.

So this.

So this is this is not bad This is very simplistic it's capacity coupled to both speakers and then capacity

coupled here.

Very simple but no bias control no gain control or whatever.

OK.

So I think what we're going to do because time is always against us here is we're gonna take a look

at this.

L am 4 6 6 6.

Now obviously we didn't do an exhaustive search here and we could just look at those other chips that

the other companies smartphone aided from Amazon we see are using but we're just trying to do this to

show the process.

OK.

So elem 4 6 6 6 now what we hope is that the tool so let's go here.

So we're gonna go to a circuit maker and again if you haven't taken the course or Section 8 specifically

you don't have to use this yet but if you don't just bear with me.

So we're gonna.

I've already created new project called C.C. Crash Course electronics beatbox AMP version ones or is

or one whatever version we get done with we'll just have 0 0 2 or something like that if you kind of

search for beatbox in my account you should be able to find this and clone it in any event.

Right now it has no documents.

So let's go ahead let's add a schematic.

We're only gonna have time to do the schematic today but I think that'll be okay.

So I'm gonna call it CCE and beatbox amp.

I'd like to name everything the exact same name.

Whoops.

V 1 underscore 0 0 1 and is that right everybody thinks so.

OK so there's our schematic and now let's go ahead let's see if we can find this chip so I'm going to

go up here and we're going to search for this.

I see.

Let's take some of this off so we have less.

We got lucky.

Look at that.

Alright so there it is right there first sit.

That's good.

Now which version is this.

This is the WSVN and looks like it's always the same and these different versions of it could mean they're

different ways that the icy comes.

So we're gonna stick to this one right here which is actually the one we're looking at Cisco place.

Place this all right.

So I can see right now I might be a little bit more room here some of the right click and I'm gonna

say sheet actions where is it.

All right.

And let's go up here and we'll go to project document options.

All right.

And I can never remember which way these goes.

And we try a one and that's massive whoops.

And so let's try a two kind of shit that.

Yeah that's that's more what I want.

I like a little bit space.

You know what I mean when I'm working.

OK so we got that.

So here we go.

So we got this.

Now let's go back here let's go back to our L 4 6 6 6.

Now typically when I do design I will

I will have this document up on another screen so I have another screen over here.

All right so that but so you can see and I going to kind of keep it here and we'll just kind of toggle

back and forth as we go here.

All right.

OK so let's look down here so here's what our basic design looks like you know fairly simple.

Let's go to a single end of design design reference.

And where did it go right about here.

OK.

All right.

So it's making a recommendation of these point three nine microfiber capacitors.

We've got this input we got this input.

We got this right here and then we got our outputs and we've got this little network right here.

OK.

So the first thing that I'm going to do is I'm going to go steal some parts.

So here is a power supply project that I did for a previous video or whatever.

So what I'm gonna do is I'm just gonna go steal some parts here.

We're going to grab these parts right here and this is the cool thing.

This is one of my manufacturing people about an LCD one of the cool things about doing electrical design

just like software you can do things kind of an object oriented way and you can reuse things.

So let's see here.

Let's go back here

and there we go.

OK.

And I'm gonna paste this here.

OK now we're gonna build this all with size 8 0 5 components.

So let's see these are 0 5.

I can see 8 0 5 surface component.

Now I talk about this at length.

When you're doing design you don't have to pick the exact part that you're going to use for passives

you can pick apart that has the right size and then as long as it's an eight or five or six of three

or four or two or whatever the size maybe you can later when you generate your build materials pick

the exact manufacturer the exact part because I don't want to sit and have exact capacitors exact resistors

I just want generic generic stuff.

And so in this case all I'm going to do is I'm going to say what I want this thing to be.

So I'm just gonna come here and I'm going to say what I want this to be and I want this to be zero point

three nine microfiber I'd done.

OK so that's one of these capacitors right here.

Now we go back here all right.

So we've basically got the end plus and the end plus are both going to go to ground through capacitor.

OK.

Simple enough.

So here we go.

So here's one right here so we'll be in plus right there.

I'm going to put that there and then W for wire mode and I'm going to copy this and notice the reference

designated right now are both c for i don't care I want to fix that later and go to the and plus like

that.

Let's get our grounds here.

So here's our ground and I kind of like putting things on the same level.

So it's kind of symmetrical so going to put our ground here we're going to put our ground here.

All right.

So it looks good so far.

Now we've got these v sub d d lines and if we look the way that they've got this is we've got a capacitor

real close to it and then we've got kind of the input coming in here with a one microphone right.

So I going to kind of enhance that a little bit.

That's not enough for me.

So what I'm going to do is going to go back over to my little power supply design here and I'm going

to steal this ferret bead Steel is very upbeat first.

All right then I'm gonna come back here.

So right now as I'm sitting here I can hear my dog barking.

She just is constantly hungry I don't care how much she eats.

She's just give me more food give me more food it's supremely annoying you can't hear it but I can.

All right.

And so we're gonna go here and then now what I'm gonna do is be careful with this.

I'm gonna scoop this over a little bit.

Like this now.

So electrically there's one thing and then when we do the layout which you're not gonna have time to

do the layout right.

That's something you can do yourself or just designing a circuit.

When you do the layout you got to keep notes to yourself and say put these capacitors close and all

that kind of thing.

Right.

So what I'm going to do here is I'm going to do this.

I'm going to actually draw these like this.

So when I put this up here and then I'm going to put this up here like this.

OK.

Now what I'm going to do is I'm going to go and get my capacitor here and I'm going to put a zero point

one microfiber at all right.

Now I've said this before when companies show these designs these the bare minimum of everything to

make things work right.

So we're not going to use the bare minimum of everything we're going to kind of you know crank things

up a little bit.

So what I'm going to do is on each of these on each of these channels I'm going to use larger capacitors.

So I just get you know better bypassing and better noise reduction.

All right.

So that's good.

So take these to copy them and put them over here because it's the symmetrical design again if you look

here.

Whereas it kind of got capacitor capacitor and the whole thing is tied together in a capacitor on the

main input.

OK.

This is going to be our main input here.

So when we get there in a minute OK all right.

And then we are going to go here here to here hear whoops.

And remember it's a W puts you in a wire mode here.

So I just pressed W. and I can press it press escaped press escape.

That takes me out of it.

Now we need to tie these two things together.

All right.

So to emphasize

Yeah I want to do this.

I think that all that kind of emphasizes All right.

And then what I'm going to do is the power we're going to bring the power in a little ferret bead.

All right.

So we're gonna bring the power in right here.

All right.

And the first thing we're to do is going to filter through this ferret bead.

Now we need a power input here.

All right.

So we're just gonna we're gonna steal one of these little power

little icons here and that's just right here.

If you just go here we could say power port here and then we could select one of these.

But I've already got it.

So let's just use it.

All right.

And then now this is gonna be the power from the output from the input to this board.

I don't really know what this is gonna be called.

So it's supposed to be about five volts so what we're just gonna call this V some see OK we just can

call it V CCC and you're gonna put that input in.

All right.

OK now I want to put some bypass capacitors here right.

Right on this input.

All right.

And let's make this nice and pretty able to do this.

Want to do this OK.

And let's tighten that up.

Let's zoom back in.

OK.

All right.

And then now what I'm going to do here is I'm going to put this up a little bit.

Forty seven microfiber you can put that to 47 micro Fred.

All right.

So this ferret beat is a high frequency filter basically.

And this can handle up to an amp.

So this is a nice little ferret bead.

All right.

So we've got our power coming in.

We've got a filter.

Then we've got it kind of bypassed and decoupled here.

Then we go down and we split the supplies we go into v CBD both ways.

And then now I'm in a no when I put this thing together these two capacitors go next to this pin.

These two capacitors go next to this pin you know keep that in my head.

All right.

Now we're looking good here.

So let's go ahead let's say that

and let me say project good.

OK OK.

So now what else do we have to do here.

Let's see here.

What else do we have to do.

OK we've got our speaker.

Now what are we going to do for a speaker.

What we can do for our speaker so we just so there's no capacitors there's no nothing which is really

good.

We just need to literally connect this to a speaker.

How are we gonna do that.

Well we could just put some pins on the board so we could do that but we could put a terminal block.

OK OK.

So we can use terminal blocks which we can kind of connect to.

And so again you could search here to see what's kind of in the library that you can gain access to.

Now I've already kind of done this.

Luckily that's why I've kind of got this design here and for this one what I'm going to do is I've already

selected these terminal blocks here which look really cool let me show you what they look like.

There they are right there I kind of like those.

So we're going to have these terminal blocks here.

Then also what we're gonna do is in parallel we're gonna put these little headers so you could plug

in with the header or you can go with a terminal block.

Right.

We're gonna kind of do that.

All right.

So what I'm gonna do is I'm going to take this part right here.

Copy it and I'm going to put it into our design here.

Okay.

And again we will mess with all of the labels for everything shortly.

And now we need a two pin header which I just showed you was also in here so I'm just gonna steal that.

Whoops we're going to steal that and right here it's just a little too pinhead or I'm going to steal

that.

All right.

There's a two pin header.

OK.

All right.

So now we're getting someplace control of some costly controls saving.

OK.

So we look here what else do we need.

We kind of made a little bit better power supply so we got our input.

We had our outputs we can deal with the input a minute we got our outputs are going to we're going to

go to our terminal block or two are header that we just put in there and just straight to it.

Nothing else.

OK cool.

All right.

And it's just that right out right out left out left out that's.

Very simple.

OK.

So I'm gonna go here and go like this and we'll go like this and we will then wire this thing straight

in boom and we wire this one.

Let's go down a little bit like this a little bit of room here like this.

And so.

All right.

And then this thing right here this just the label here.

All right.

And we're just going to say just say two pin header.

All right.

And what we're going to do is each one of these is going to just connect directly to this also.

All right.

Let's keep the pins the same.

So this is the right to left to and right two and left one right one.

So let's put the one pins on the one just to be consistent and that's another thing when you're doing

anything with stereo equipment or audio stuff you've got right and left channels right.

So what that means is if you hook something up in one way and you flip it audio will be out of phase.

Right.

The speaker will be pushing while they're the ones pulling so be careful plusses and pluses minuses

and minuses.

Labels are important too is what I'm saying.

All right.

So my electronics teacher back in high school his name was Kenneth Barron and he had a story one time

about some very expensive equipment that they installed for a high school something some kind of show

that was going to be in the gymnasium that week.

And they had it all set up and the audio just sound horrible.

They couldn't understand what is going on.

This is his high end equipment.

And then the students said wait a minute maybe we should flip the speakers plus to minus minus plus

they did and then they put them both in face so both speakers are pushing and pulling at the same time.

But because they other labels wrong.

So always kind of be very consistent with things.

OK.

All right.

So that looks good.

OK.

And then.

So now I don't need to say what this is.

I'm gonna call this audio out and this is what left audio out left right.

That one correct.

Good.

And this one's audio out left.

Whoops and again you know it may look easy talking and doing it at the same time.

But believe me I'm not.

There's nothing I'm editing out here really.

It's just all in real time so I'm just kind of doing this as I go.

Let's see this onshore technology we do need these part numbers on this one.

So this one is important to keep this exact part No this onshore technology.

So there it is there.

So I can I can lose it right here if I want to.

So what I'm going to do is I you know what I'm just gonna leave that right there.

A lot of times I won't leave the part numbers.

This is just a generic 2 pin it looks like this.

Well doesn't exactly look like that's what it looks like going to the board.

And then these are just going to be the holes in the board the footprint which you can put a two pinhead

or an OK so that all looks good.

OK.

So we're getting there.

That looks good.

And then we've got the skin select and shut down.

All right.

So shut is active low.

Right.

So shut down active low.

And then game select is up to V CBD.

So we are going to four shut down.

We are going to just make this a kind of a pin header and maybe we can make it an input and we'll just

kind of pull it high.

So for shutdown let's start off let's just pull this high.

All right.

So that it's not loops so it's not shut down so let's get a couple resistors here we find a resistor

and you know what.

As a matter of fact let's take this whole piece because I want I want some kind of power indicator.

All right.

So right by this power indicator.

And so this is a piece of C in you know what I like that name better.

All right we're gonna call it that for 70 LCD one blue LCD that's cool.

Now I want this resistor.

And now what I'm going to do is up here so this is a shut down pin.

So in this shutdown pin I am going to

connect it just like this and we're gonna go to the east of S.C. and we're gonna pull this thing up

and we can you know there's a lot of different ways that people like to design things.

Let's put this here.

I kind of don't like to put things in between things I'd rather pull it out so we can let's just pull

this whole little pin out like that.

We can do that or we could put it up right here.

That's another option.

We can do that.

So do this and again you know I don't need to do all this but I'd like you to see what I'm thinking.

So you've got enough room here.

Yeah it's OK and let's move this over here a little bit great.

No thanks.

Doesn't work.

There we go.

All right.

And then we're gonna move this back here and what I'm going to do is some pressing spacebar which kind

of does all these rotations and it's not going to it's not being cooperative.

That's exactly what I didn't wanted to do.

All right so nobody is going to break this.

Now going to take this resistor and rotate it.

There we go.

OK.

Now to put this game select here like this.

Now I want to put this FCC here.

OK.

Now this pen right here.

This is gonna be our control.

All right.

So we're gonna we're gonna bust that out at some point but now we've got this thing doing what we want.

Okay so that looks good.

That was on the shut down control we're gonna do the game select momentarily wants to read out a user

thing.

Okay.

We need these input capacitors.

Let's go do this.

Somebody copy that rotate that and where our inputs here's our input minus.

So there's our input minus.

And whereas our other input minus.

Right there.

Okay.

So going to do that and they're saying use the same value.

All right fine.

Okay.

So this needs to be brought up a little bit.

Let's go here.

Let's bring this up just a hair.

Good.

OK.

And then we're gonna bring this up here.

And again there's you know a lot of different ways to do layout.

And as you do this you can kind of clean it up do things differently you know whatever suits you.

OK now we need our input.

Let's go back here.

So basically it's input to ground input to ground so we're gonna do this exact same thing.

So I'm going to take one of these guys right here.

We're going to do loops.

We are going to flip it around.

All right.

An will do the exact same thing so on pin one.

That's gonna be the input.

All right.

And pin two is gonna be the ground and get a ground here.

So it's gonna connect to ground force all right.

And you know you can do this also.

There's nothing wrong with doing this.

Putting a ground like that you can do that.

Right.

There's nothing wrong with that.

You can do that.

All right.

So you're gonna do this.

And we're also on the inputs we're also going to put these headers so we kind of have the ability to

a header in.

So you just have to give ourselves enough room.

All right.

Now on this right here there's no plus and minus here.

So we can't make these the same but we're gonna make the input consistent so whatever we do so pin one

is gonna go here all right.

And then pin 2 is gonna be the ground on both of these.

All right.

So pin 1 is input into who's gonna be the ground so we can tie these together like this straight down

the ground.

And we're gonna go like that.

Okay.

There we go.

So we have both inputs you can use this one or this one and then it's gonna go to our input okay.

That looks good.

So just go copy this block.

All right.

I'm going to copy that block.

We'll put it right there and then we're going to go here.

We're gonna go here and then we're gonna pop this up and pop this up and go like that.

So that looks good.

Now this is not audio out left anymore.

This is audio in audio in and I think is it right.

Yeah.

This one is right.

Audio in right.

And this is audio in audio in left.

Okay let's move this out of the way put it right there.

Whoops put it right there.

And again you know you can sit here and make this really really pretty right and label things kind of

move things around.

But we're doing pretty good.

OK.

Let's put up let's put a big label on the whole thing.

Make it a big font.

Boom.

Or just steal that lots of stealing good will come up here and I'll just put this here and it is gonna

say stereo audio amplifier.

Cool.

All right.

And what's it called.

I gave it a name.

Tonight I called it the Beatbox app.

I don't put a dash OK beatbox app Sarah auto amplifier looks good.

OK.

All right.

So we're getting there.

You got the outputs that's done this DRP.

We got to see what that does.

We've got this signal right here which is going to be pulled up so will not be shut down.

It'll be running.

So this signals right here.

So now let's go ahead.

Now for kicks let's just use a label here and we're gonna go here.

I don't use.

I want to support label.

I prefer these.

So let's pull this out just the loops pull this out just a little bit.

OK.

And now let's get a port label here K and K and what are we gonna call this.

This is shut down.

So we're gonna say shut down and we're gonna put a little N on it.

Meaning it's active low.

OK shut down an active low.

Fine and then you still remember you can run wires all over the place or you can put labels on things

and then work with the same labels are those nets will connect right.

So we don't necessarily have to wear in wires everywhere and make it a super big mess.

But but things like this the audio outputs the out of the inputs you know they're very close to the

chip so you might as well put those as wires design those wires.

OK.

So that our power LCD.

Things are looking good and now so.

OK.

So now we're going to figure out what this code game select business school read about this.

OK.

So gain select and gain select.

OK.

All right.

Let's see what it says

OK Oh so it looks like you only have two selections.

So if you put it a high you get six DV.

If you put it low you get 12 DV decibels of gain.

Right.

And we've talked about a decibel measure for power gain for voltage gain and power gain.

It's either 20 log 20 log of the ratio of the input output or output input.

Excuse me or it's 10 log.

So if it's power game it's 20 log the ratio and if it's voltage gain it's 10 log.

The ratio is just a measurement a logarithmic scale of gain if you're taking the class.

So anyway I think it looks like that.

Yeah you just selected high and low huh.

So let's go through here all right.

Gain select function.

Let's read this.

I'm not going to read it out loud to you kind of.

If you can hopefully you can see this with me.

Let's just kind of read through here.

Huh.

Okay so it looks like it looks like

this pin

higher low.

It selects a gain of six or 12 DV

OK so what we're gonna do is we're gonna do the same thing here.

We're gonna pull it up.

We're gonna pull this up to V CBD and then we're gonna make it an input.

Ok we're gonna we're gonna literally kind of copy this circuit here.

Hopefully we have enough room.

So I'm gonna do this same circuit twice and we're gonna have kind of an external input that controls

the game.

All right.

That's one way to do it.

So let's see.

Can we can we scooch this over a little bit.

Give us just a little bit more room.

You know what I think.

I think we got enough room here.

Let's do this.

Okay.

So also on this pull up let's fix this.

Let's make that 10k.

All right.

For that pull up and then let's go ahead and we're going to copy this and do we have enough from so

if we put it there we don't have enough room.

So let's go ahead.

Let's scoot.

This whole I see over here and put that there.

Be very careful when you're scooping things right because you don't want some see like what just happened

right there.

Look at that.

Oh yeah.

You got to be careful.

All CAD programs are DOS programs basically so they're very old and they have really weird artifacts.

You got to watch what you're doing.

Be very careful.

Watch what you're doing.

OK.

So that seemed to work.

So now I'm going to grab this OK and

right about there.

I don't like things touching someone with a voiceover over one can grab the wrong thing.

There we go.

OK good.

So now I'm going to put this right here and this is gonna go here and this is gonna go to this pull

up here now this pull up might have to be a little bit lower it probably doesn't require any current

we could look at the data sheet to sandwich current this is going to sauce or sink when we select gain

but we'll put it a 10k and hopefully that'll be enough to hold it all right and we're gonna make this

an input OK so I'm going to call this gain and is it just called gain select Yeah so when called gain

Select All right.

And now OK so then let's go here and uh Io type we're just gonna call it by directional it's not by

directional but I like the symbol.

All right.

I don't I don't take the time to make all these different ports inputs or outputs or this or that because

it's just too much work.

Drives me nuts.

OK all right.

So that's that.

So now both of these will be pulled up so it'll be in the gain mode when it's high.

So if you go here and we say for differential gain of 60 we should be perfectly connected to v CBD or

driven logic high for differential gain of 12.

It should be to ground.

All right.

So the bottom line is if it's a low it's going to be higher again.

So I'm going to put it lower gain mode so it doesn't blow something up.

All right.

That's good.

One last thing.

These colors are driving me crazy.

So the full color I'm just going to make this support will make it this little blue color and we're

gonna make the border color black color and we're going to make the text color a black color.

So this looks all right.

That doesn't look very good.

Let's make the text color with the text.

Go make the text color white.

OK that's better.

All right.

Just you know everything doesn't have to be completely ugly and uh was that one and the text color was

white.

Again I'm just showing you things as we're doing this also the border is black and

and you know it.

Well you know what let's just let's just make these different color to represent.

There's know different things.

How about let's make this one kind of this green or aqua color ness of it too much even for me.

Let's make it kind of a dark

brown color kind of whatever.

All right.

So now we're getting there.

What time.

OK.

We're doing OK.

We're about an hour in.

Let's see here.

So what are we missing.

So we've got this gains like now.

Let's put this out.

Let's put this out to some some kind of control port so we could do the same thing.

OK.

So let's think about this.

We could do the same thing with.

We could do the same thing with these ports these terminal blocks and so that so that we could control

this externally because maybe you want to plug this into something and control the gain.

Or we could control it with a switch we could control it with a switch right now for shut down.

So all right so what I'm going to do is this and again this is just design.

It's you know whatever you want so let's do this.

Let's we're not going to put these two terminals but we're gonna put them to a header.

Let's put them both to a header so they could externally be controlled if you want to control it.

All right.

The thing will not be shut down in default so it'll be running the game will be low and we'll put it

to a header and if you want to do something with it you can't through the control of the header.

OK so let's go ahead and let's do this.

We're going to go here and we're going to let you know what.

Let's yeah let's do this.

So let's just show the use of these port pins all right.

So now I'm going to put them right here and then what I'm going to do is these are basically wherever

these are we'll connect to these lines here.

So I'm going to take one of these guys and I'm going to go here and then I'm just going to put this

right here.

So this is and we're gonna call this a game slash shut called shut down and these are just notes.

Right.

This doesn't get printed on anything.

All right.

And so now we're going to make a pin one is gonna be the shutdown pin and pin two is gonna go to this.

OK.

So those two go there so that you can access them from the external world.

Now on the game select I also want to have the ability maybe with a switch to change what this thing

is.

So let's add a switch.

OK.

So let's add a little slight switch and I think yeah.

Where am I see this little slight switch right here.

This is a really small switch.

There's a company called E switch which makes a lot of cool little switches.

So we're just gonna use this.

OK I can get it to select good.

All right.

OK so that are a little slight switch right here and we are going to basically in one position that's

going to turn the switch on it's gonna turn it off in the other position okay.

So what are we going to do.

We want to ground this thing so I'm going to take this to the ground it here all right.

And then in the other position it's going to do this.

So when it's in one position it'll do nothing.

So I'll just get pulled up high up here and then once you have the position It'll ground it and then

at worst case we'll have a circuit with a 10k drop dragging current through here so it's not going to

hurt anything.

OK.

So now what is this thing called this switch here.

Let's look let's put a little name on this so this is a e.g. 12 17 so we can leave that label what that

is right there the value of it so you know what.

You know the part number isn't because we're gonna use this specific switch just like this specific

part right here but let's put a little label on it and what I like to do is do this and let's just shoot

this text down to about twelve point font whenever you do anything messing with fonts or whatever this

tool circuit maker I think it goes to the cloud and download stuff I'm not quite sure because funds

are already loaded on the computer but I don't know what it does but it seems like it's going to the

cloud for some reason and downloading things.

Who knows.

So it takes it about 30 seconds.

There we go.

All right.

And let's small in this font maybe to size 14.

All right.

That's good.

All right.

Then we can put this right here.

And so what is this.

Everybody this is the.

What is this game.

Select six slash twelve DV OK and we're going to have to know which way is which we would do that on

the PCV itself.

We would put some writing so we could say 60 B or 12 DV on the PCV.

All right let's move this a little bit out of our way.

All right cool.

OK.

Looking good looking good.

Let's see here now.

What else do we have.

OK we've got power we've got to bring the power into this thing.

So right now we're bringing the signals in on terminal blocks.

We're bringing the signals out on terminal blocks.

Let's go ahead and bring the power in on a terminal block also.

All right.

Why not.

OK.

So we're going to just we're going to kind of bring the power in.

Typically I bring the power in the top left of the design.

OK so what I'm bringing in right here.

All right.

Just like that as simple as that and pinned to here is ground pin to here is ground so just be consistent

and make this pin to ground.

Again it's not going to matter but I just like consistency.

The less you have to remember when you're doing electronics the better.

So if you have conventions better.

All right.

And then here's recency.

So here's where recency is gonna tie to.

Now if there are other devices on here I would have some filtering on this input but there's only one

ship and it's already got its own filter so we're just gonna bring that in there and that's that.

OK let's see.

All right.

What do we got here.

All right.

So we have we've got our input here.

We've got our other input here.

We can come in both ways on a terminal block or on headers.

We've got our filtering capacitor here which is basically going to block DC and whereas our kind of

reference design our crude reference design which is the bare minimum usually there it is.

All right.

So we're doing this one.

All right.

We've got that hooked up.

We've got capacitors to ground.

So this is very important a lot of times when you have a differential input and you want to use it in

single ended mode.

Be careful don't just hook the other end to ground a lot of times you have to get through a capacitor.

All right.

Be careful of that so that AC can pass through here.

All right.

And those are point three nine.

Is that the recommended one and those may be wrong.

There may be better values to make those at maybe point four seven point two to maybe one microfiber.

So we play with that in our design.

OK.

We've got our filter which we did our better filter up here which is a much more robust filter it's

got a high frequency very be that it's got really good bypassing on the inputs we've got a stable power

supply.

Then we split it off and then we bypass with a high and a low so we get a low noise then we also have

a 10 micro ferrets for a charge so we can get to that current when we need it and then gain select.

We just know that it's high and low shut down is low.

So we're gonna pull it up high so in default the thing we'll be running the outputs no magic there it's

direct connection which is what we like about this I see.

OK.

So that is that and that is about it.

And let's see that's it.

We've got our LCD we're all good to go.

OK.

So now one problem we have is all the reference six designations are all over the place.

So now you can let the system do it.

So let's go look at that.

And you know I use so many tools everybody an enormous amount of tools because they do software and

hardware and firmware and mechanical that you know if I don't use something for a week I forget where

certain things are.

OK.

So now what we're looking for is we are looking for to be able to label all of the reference designations.

So we're looking for that option.

So it's not here in view definitely not there in home.

So there's net label here component junction directives.

No it's not around.

It's not here in Project commit an existing variance template.

No it's not there tools tools tool schools no sheet.

Yes.

This is where it is it's in tools.

OK.

So under annotate if we go here and we say annotate schematic that is reset twenty six changes and

that is not what I wanted.

Reset duplicates

reset duplicates so that's what.

Okay so that reset there is a way to annotate the entire thing.

What's the attitude schematic entity scheme adequately force annotate on all schematics.

Yes.

OK all right.

There it is.

So anyway so that went through and annotated everything and made sure that we don't have any duplicates.

Now you can also go through manually which is what I prefer to do it just go through manually and kind

of a sensible way.

If you have you know hundreds of thousands of parts that a lot of times it's a lot of work but a lot

of times I'd like to keep you know my capacitors resistors and block so I know where they are in the

design.

But anyway this looks like it did it right and rock.

So twenty two teeth 5 23 T4 kind of jumped over there.

We've only got one resistor here are two or three.

We've got one FP one the capacitor is all look pretty good.

So anyways that's not bad.

OK.

So we'll stick with that.

OK.

All right.

Now we're we're ready.

So now what I'm gonna do here is I'm to say this project and then I'm going to commit the project and

this is the first time that I've done it.

So it's all good to go.

Now what I'm going to do is I'm going to right click on here and we're gonna say compile all right.

And as we compile we we saw no errors so there's no problems with it.

All right.

So that is it.

So that is our schematic for our amplifier.

So what's the next thing we're not going to do in this video.

We don't have time to do it but the next thing that we would do is we would go to our project here and

we would say add new to project and we would say add a PCV.

Right.

And then we would name this PCV and then we'd go ahead do this real quick but we're not going to finish

it.

We just don't have time beat box app and version 1 0 0 1.

I was you know I always feel like I'm keeping you guys after class you know.

And I know everyone likes to get done.

OK.

So there we go.

OK now we've got this and now we're going to go back here.

So we've got this thing right here and then what we do is is let's recompile this one more time and

then what I'm going to do is we're going to save the project we're going to commit the project.

This is just me making sure everything is all hunky dory OK.

Now if we go here there's nothing there.

Right.

So then what you do is you can go up here to home and you go to project and then you go import changes

from C.S. beatbox that into and then this is going to push all of this stuff.

So we say validate they validate changes we say execute changes and of course in section 8 is a whole

class a whole course as big as a whole course on PCV design.

All right then we can say close.

And then all of our parts are right here.

So then we would just start placing them in a sensible way.

So maybe we can do that another video and then if we want the 3D viewing go here all right and we can

see what they kind of look like exactly what we expect.

OK.

So everything is as it should be.

But what I wanted you to do is I want you to see the process.

So here is an amplifier.

So this should work.

We've got good power we've got power coming in.

We've got our right input we are left input we've got our left output we've got the right output we've

got different ways of getting the signal out different ways getting a signal end in default the chip

will be enabled the game will be selected at six D.B. or we can control it with our little switch here

to switch it into 12 D.B. we want to get some more gain out of it and that's it that's it everybody.

So there you go.

So there is an amplifier in real time how my thought process works a fraction of what the things that

you have to do you can look at what other people have done you can go look for eye sees a different

vendors and go through a mall.

Now if we're really going to do this as a professional product we'd spend a weekend just looking for

chips right then we'd maybe spend a week or two evaluating some chips and we get some Dev boards maybe

two or three weeks right then we've kind of say hey we really like this chip it's got a good price it's

really available then we've built some prototypes of it like we're doing here lay out the PCV send it

out evaluate it test it verify it and then say like this is cool I'm gonna make a product out of this

bam right.

And that would be it.

So that's it.

So what you can do is you can look for this projects CCE under beat box AMP underscore V1 underscore

zeros or one right beat box AMP under my account on circuit maker if you want to download this and finish

it up or play with it and make your own version of it.

And I'm curious.

I don't remember using this chip but I mean you know who knows maybe I have but I'm curious to see how

this how this works and if it's a nice little amplifier.

So anyway that's it.

So I will see you in the next lecture by.
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