An op-amp (operational amplifier) circuit is a device that amplifies the difference between two or more input voltages. Op-amp circuits are the most widely used electronic devices in the world due to their integration in a wide variety of electronic goods. There are many op-amp circuit variations available and several types of differential amplifiers that are made by using several op-amps together.

How Op Amp Circuits Work

Op-amp circuits take a voltage from two or more inputs, amplify it, and usually feed it back to the voltage source. Op-amp circuits include one or two power supplies, two or more input terminals, a circuit, and an output terminal. As each input terminal receives a different voltage, the op-amp attempts to make the two voltages equal by amplifying the difference between the two voltages and passes the resulting voltage to the output terminal.

Applications

Op-amps are most notably used in integrated circuits that have revolutionized home computers, mobile devices, and portable servers. They can be found in many different types of sensors, detectors, and converters. Op-amps are also used in oscillators, rectifiers, and audio-video frequency buffers. Additionally, op-amps are used as filters, voltage clamps, and voltage and current regulators.

Advantages

Op-amps are extremely cheap to mass produce, are small enough to fit into a wide variety of electronic devices, and can withstand a wide temperature range. Additionally, nearly all op-amp types can substitute another type of op-amp. Op-amps also have high gain, a virtually infinite frequency range, and high bandwidth.

Disadvantages

Op-amps have a finite bandwidth that limits their capacity to amplify a signal. They produce random voltage discharges at their input terminals, usually due to noise and thermal effects. Op-amps also produce a small amount of current that leaks back into the input terminals, causing voltage levels to drop. As the current accumulates, each terminal’s voltage level eventually becomes the same. Because op-amps can only amplify the voltage difference between the two terminals, they will eventually have no effect at high voltages.