Also known as op-amps, operational amplifiers are integrated circuits that help intensify weak signals. These ICs are made up of three terminals: one output port (low-impedance) and two input pins (high-impedance). The input pins are non-inverting (the one using a + or positive sign) and inverting (uses a – or negative sign).
Op-amps are versatile, which is why they are popularly used for analog functions like control, power, and signal chain applications. Operational amplifiers function by amplifying the voltage difference between the two inputs.
Op-amps are a type of differential amplifier and can be sold as standard integrated circuits operational amplifiers or hybrid/integrated operational amplifiers. They are also often packaged as elements or components of complex ICs.
Operational amplifiers are used for a variety of electronic devices, including industrial, scientific, and consumer devices.
Operational amplifiers are classified into four: current amplifiers, voltage amplifiers, transresistance amplifiers, and transconductance amplifiers.
- Op-amps that take a current input and produce a current output are called current amplifiers.
- A voltage amplifier receives voltage and produces voltage at its output.
- Transresistance amplifiers are operational amplifiers that convert current inputs while producing voltage outputs.
- Operational amplifiers that convert voltage input into current outputs are called transconductance amplifiers.
The following are some of the top characteristics of operational amplifiers:
- Infinite open-loop gain
In an open-loop gain, the feedback loop or path is open. The open-loop gain pertains to the measure of gain when the circuit has no feedback.
- Frequency response and BW or bandwidth
Ideal operational amplifiers are capable of maintaining a high gain no matter what the signal frequency is. Higher bandwidth means higher gains and frequencies resulting to improved performance.
- Input impedance
Op-amps are equipped with high input impedance, which refers to the measurement between positive and negative input terminals.
- Output impedance
An op-amp’s small-value output impedance determines its capability to function as voltage buffer and how much current it can drive.