1. Operation amplifier

The operation amplifier is the most important electronic part in electrical analog computers.

The term operation amplifier was introduced and defined by John Ragazzini in 1947:

“As an amplifier so connected can perform the mathematical operations of arithmetic and calculus on the voltages aookued ti its input, it is hereafter termed an Operational Amplifier.”

In it’s simplest integration, the operation amplifier can be found in analog computers in so called open amplifiers, where the positive input is eleictrically grounded while it’s negitave input is connected to an input resistor. This is used to generate inverse functions (e.g. a multiplier in combination of an open amplifier functions as divider).

The operation amplifier is also the only active part in summer and inverter circuits.