Operational Amplifier Concept

An operational amplifier is an amplifier with two input terminals and one output terminal. It amplifies the voltage between the two input terminals at a very high rate and then transmits it to the output terminal.

Operational Amplifier Logic Coincidence Diagram

If the operational amplifier is represented by a circuit symbol, it can be represented as a triangle as shown in the figure on the right. Its two input parts are called non-inverting input (1N+) and inverting input (IN-). It amplifies the voltage between the inverting input terminal and the non-inverting input terminal with a great amplification rate, and then outputs it from the output terminal (OUT).

A package that contains one operational amplifier circuit is called a single operational amplifier, a package that contains two operational amplifier circuits is called a dual operational amplifier, and a package that contains four operational amplifier circuits is called a quad operational amplifier. The circuit using a quad operational amplifier can be smaller in area than a circuit board assembled using a single or dual operational amplifier. In almost all packages, if it is a single operational amplifier, a tube shell package or an 8-pin dual-in-line package is used; if it is a dual operational amplifier, an 8-pin dual-in-line package is used; if it is a quad operational amplifier, a 14-pin dual-in-line package is used. In addition, in general, the arrangement of the pins is generally universal, although there are exceptions. For operational amplifiers used by amateurs, only the above-mentioned packaging methods may be used. Therefore, it will be very convenient to understand the distribution of this lead.