An op-amp (operational amplifier) is a high gain analog voltage amplifier with differential high impedance inputs, and a low impedance output. A basic building block in signal processing, like as amplifier or active filter.
An opamp is a high gain amplifier, which amplifies the voltage difference between its two inputs.
An ideal opamp has the following properties:
- infinite open-loop gain
- infinite bandwidth
- zero input current
- zero output impedance
- zero offset voltage
Real op-amps often have gains of minimum 100 dB, which makes them of little use without feedback. Negative feedback is most often used, and allows the design of inverting amplifiers, non-inverting amplifiers, integrators, differentiators and filters. Positive feedback is used to construct Schmitt-triggers.