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Solid State Amplifiers => The Newcomer's Forum => Topic started by: saturated on November 07, 2024, 11:05:16 PM

Title: A new book [Op-Amp experiments]
Post by: saturated on November 07, 2024, 11:05:16 PM
Check it  xP

IMG_20241107_215502240_HDR.jpg

IMG_20241107_215541321.jpg

Briefly looking through it it has tons of experiments where he has you make little circuits to make and do cool stuff.

Like....make an op amp differentiator.  And integrator.




Title: Re: A new book [Op-Amp experiments]
Post by: saturated on November 26, 2024, 03:16:26 PM
Good afternoon esteemed members and Mods

I want to begin some experiments in this book
IMG_20241126_082755378.jpg

IMG_20241126_082722846.jpg

Right off the bat 🦇 I need a 741c

I have a stash of old ic but no 741 c

So looking at digikey there are many different ones (or same ones)

I was able to weed out about half because they are surface mount and I need eight legged DIP

Also there are some Kool TO-99B but they are $17 a piece

The ones that look suitable all have additional prefixes

LM741C-MWC

UA741CPG4

LM741CN

LM741CN/NOPB

UA741CP

maybe I need to compare pinout and data sheets  :grr
Title: Re: A new book [Op-Amp experiments]
Post by: g1 on November 26, 2024, 07:02:41 PM
The MWC suffix part is also surface mount.  Any of the others will work.
The letters in the prefix designate the brand of manufacturer.
Title: Re: A new book [Op-Amp experiments]
Post by: saturated on November 26, 2024, 07:10:46 PM
Thank you sir

I just enjoyed reading about Burr-Brown I had actually never heard of them until now.

Btw happy holidays to all of you  :dbtu:
Title: Re: A new book [Op-Amp experiments]
Post by: saturated on December 01, 2024, 03:39:47 PM
I have a few items in cart at digikey I'm gonna finish my list tonight and get this stuff on the way.

This is some good stuff because I already have a problem  :tu:

So I'm looking at this diagram and getting stoked about doing it  :dbtu: but then I'm like oh no...
IMG_20241126_082755378.jpg

How do I get a minus fifteen volts on the device  :grr  xP

So I had what I thought was a major epiphany and said ah ok just hook the neg of the power supply but make sure the neg is ungrounded
IMG_20241201_132840406.jpg

Being proud of myself 💪 I said yeah I can test this and made the following circuit on breadboard.  And it didnt work (fortunately)
:loco
IMG_20241201_142055183.jpg

Since it didnt work I figured ok maybe my negative is connected to ground so I checked for continuity and resistance and they are not connected.

To add to the confusion  :loco as I type this I anticipate that perhaps the Op-Amp will show -15v because for lack of better words (maybe ?) it's not resistive.  Sorry for opening a can of worms.

But at least I'm getting out of the "dude...neg is ground" mindset.  Because sometimes it is.

I'm kinda glad I get to order a green 💚 jumper cord. 



Title: Re: A new book [Op-Amp experiments]
Post by: g1 on December 01, 2024, 07:31:17 PM
For your positive supply you have the neg. lug connected to ground, yes?
For the negative side you connect the positive lug to ground.
Title: Re: A new book [Op-Amp experiments]
Post by: Tassieviking on December 02, 2024, 11:33:04 AM
If you have two 9V batteries and you want 18V you connect the plus of on battery to the minus of the other battery, result is 18 Volts.
Where the 2 batteries meet is what we normally call ground, and then you have plus 9 volts and minus 9 volts on either end compared to the ground.
From the minus 9V to the plus 9V will be 18V

On some schematics they just say 0V, 9V, 18V instead of -9v, ground, +9V.

There are so many variations but after some time you just know what they are with a quick glance.

I find having a positive and a negative supply with a ground much easier to trace and understand  a circuit because sine waves have positive and negative sweeps, just think of that oscilloscope waveform where the middle is 0V or ground.
Title: Re: A new book [Op-Amp experiments]
Post by: Tassieviking on December 02, 2024, 11:49:07 AM
I just had another look at that power supply you have, there are 2 switches on it.

IND would mean the 2 outputs are separated from each other, not connected to each other at all.

SER would mean in series, I presume that this links the 2 outputs so you have a +,0V, - output.
SER will give you  double the voltage of one output but no more amps.

PAR would mean parallel and the two outputs will be joined up with + to + and - to -, you get double the amps compared to one channel but also only the volts of one channel

Try it with the switches set to SER and then measure the voltages of the 2 outputs, I imagine the plus on one side is equal to the minus of the other side.( they will be linked by the switches internally)
Title: Re: A new book [Op-Amp experiments]
Post by: saturated on December 02, 2024, 12:47:44 PM
Thanks guys  :dbtu:

I have to go through my stuff and see which of these resistors and capacitaters  xP I have and don't have
IMG_20241202_122113531.jpg

Shouldn't take more than a couple of weeks  :loco
Title: Re: A new book [Op-Amp experiments]
Post by: saturated on December 06, 2024, 06:36:41 PM
A major technological advance has been made.  :lmao:  Negative voltage has been achieved  :dbtu:
Thanks to G1 and Mick  :tu:

IMG_20241206_172643487_HDR.jpg

IMG_20241206_172709007.jpg

So per instructions the (+) is connected to to ground on different power supply.

Pretty cool I confess I was fearful of some 🎆🎇 fireworks

I guess the important part is the negative of the power supply must not be grounded.  Then it would be the fourth of July  xP

So that's cool I have my chips and stuff on the way and it seems to be a common theme with these guys to connect V+ and V-

But then other ones had stuff like Vc and Vd but I'll worry about that when I get to it.