Op Amp Basics by Analog Devices


#1

This is a great PDF resource from analog devices, especially if you’re doing any signal chain work in the near future:

http://www.analog.com/media/en/training-seminars/design-handbooks/Op-Amp-Applications/Section1.pdf


#2

The whole book can be viewed/downloaded here: Op Amp Applications Handbook


#3

AH! Didn’t realize it was just a partial. Thanks!


#4

I am trying to learn more about op amps but haven’t done much with them yet. Is this a good beginner book? Or should I start somewhere else?


#5

Hi @JasonR,

Do you want to learn theory or just build a few circuits and use them?

Many opamp circuits, such as the inverting amplifier or a lowpass filter, have simple formulas and one doesn’t need to know a lot of theory to use them, especially in low frequency/audio applications. Building a few of those on a breadboard and looking at their input/output behavior goes a long way.

if, however, you want to know how they work internally or perhaps where their limitations are, the handbooks are excellent.

A slightly more hands-on resource is The Art of Electronics book by Horowitz & Hill.

Of course, asking specific questions on this forum is encouraged.

Regards,
Niels.


#6

I’m just looking for basics right now. I want to do a small audio project and heard that those are usually done with op amps. Is that right? If so, which should I be looking at? Have you ever done op amp based audio projects?


#7

Hi @JasonR,

Opamps are perfect for audio!

Most audio designs use TL072 or NE5532 opamps. You can get opamps with less distortion, higher bandwidth or lower noise specifications but the two mentioned are already quite good, readily available and cheap!

The TL072 has a higher input impedance than the NE5532, meaning that it will behave more like an “ideal” opamp (no current goes into the + or - inputs). The practical side of this is that you can use higher-valued resistors without the circuit doing unexpected things.

The NE5532, has lower noise but a lower input impedance and a lower gain, meaning that it will behave a bit less like an “ideal” opamp than the TL072.

I use the TL072 90% of the time and use the NE5532 when I need less noise.

A thing to note is that both the TL072 and NE5532 are not so-called rail-to-rail opamps. Neither their output nor their inputs should go within say 2V of the supply rails. So if you supply your opamps with +12V and -12V, you should be able to handle signals from -10 … 10V. You can find the exact limits in the datasheets under “Common-Mode Input Range” and “Maximum peak output voltage swing”. If this all sounds confusing, don’t worry, just build some circuits and experiment!

A great thing about opamps is that they mostly use the same pinout (check the datasheet first! :slight_smile: ), so you can exchange them when you use DIP packages + sockets.

Ask questions in the forum if you run into trouble.

I run a company that makes synthesizers, so yes :slight_smile: I have used opamps in audio circuits.

Regards,
Niels.