**I need to know about operational amplifier****s (OP AMP).**

An *op amp* is a voltage amplifying device. It can perform mathematical operations such as addition, subtraction, multiplication, division, differentiation and integration.

Also an operational *amplifier* is a DC-coupled high-gain electronic voltage *amplifier* with a differential input and, usually, a single-ended output. *Op*-*amps* may be packaged as components or used as elements of more complex integrated circuits.

Hi...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.