How does a operational amplifier works?

Question

please don't give me links to wikipedia. Other links that are helpful are welcome though

Answer 1

Basically it works by using IC transistors and resistors and capacitors connected as a DC amplifier so as to provide a differential amplifier of very high gain, and very low offset voltage and current.

for details:

http://en.wikipedia.org/wiki/Operational...

Answer 2

It's hard to understand exactly what you want, because your question is so all-encompassing.

If you just want to use op-amps, here are some basics that might help.

When used with feedback components, just consider the amplifier as having ∞ gain.  That makes calculation very easy.  

Also, consider both inputs as having an ∞ input impedence.  This also makes calculation easy.

For small amplification, consider the op-amp frequency range in the kHz.  Large amplification causes the op-amp to react too slow for audio applications.

For the output, they are usually capable of driving about 20 mA.

There are 2 classic configurations of op-amps as amplifiers - either inverting or non-inverting.

With an inverting version, the gain is given as:

Vo = -Vi x (Rf/Ri)

With a non-inverting arrangement, the gain is given as:

Vo = Vi x (1+ Rf/Ri)

Adding capacitors to the input or feedback loop can get the op-amps to act as differentiators or integrators.

Obviously, you can get op-amps that are specially designed to do certain things very well, but the above gives you an idea of how a garden-variety device works.

Here's a good primer on the basics:

http://zebu.uoregon.edu/~rayfrey/431/not...