How does the operational amplifier work?

Answer 1

The operational amplifier is a device with two inputs, and one output. One input is called non-inverting, while the other is called inverting. Sometimes, there are two outputs, in which case one is also non-inverting and the other inverting.

Within the limits of the design of the operational amplifier and its circuit, the output will assume whatever state is necessary to make the two inputs equal to each other. The output goes in the same direction as the non-inverting input, or in the opposite direction as the inverting input.

Note that for the operational amplifer to work correctly, there needs to be some kind of feedback loop, usually from output to inverting input (we call this negative feedback), so that the output can track one of the two inputs in the ratio of the bridge that is setup in the circuit design.

Answer 2

Hi there,

I've written a post explaining this idea in simple terms. Hope you enjoy it!

http://chrisgammell.com/2008/08/02/how-does-an-op-amp-work-part-1/

~Chris Gammell