An operational amplifier is a circuit unit with a high amplification factor

An operational amplifier is a circuit unit with a high amplification factor. In practical circuits, feedback networks are usually combined to form a certain functional module. Due to its early application in analog computers to achieve mathematical operations, it was named "operational amplifier". An operational amplifier is a circuit unit named from a functional perspective, which can be implemented by discrete devices or in semiconductor chips. With the development of semiconductor technology, most operational amplifiers exist in the form of single chips. There are various types of operational amplifiers that are widely used in the electronics industry.

Standard or general-purpose operational amplifiers are relatively inexpensive due to their high demand and output, but special purpose operational amplifiers may still be sold at a price of over 100 times that of general-purpose amplifiers.

Operational amplifiers are widely used devices that are connected to appropriate feedback networks and can be used as precision AC and DC amplifiers, active filters, oscillators, and voltage comparators. They are widely used in the fields of household appliances, industry, and scientific instruments.

Operational amplifiers are extremely high gain amplifiers with differential input and single ended output, commonly used in high-precision analog circuits, therefore their performance must be accurately measured. However, in open-loop measurements, the open-loop gain may be as high as 107 or higher, while pickup, stray current, or Seebeck (thermocouple) effects may generate very small voltages at the input end of the amplifier, making it difficult to avoid errors.