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.