ODWS icon The Open Door Web Site
Site Map
> Electronics
History of Science and Technology
Math Studies
Learning French
Study Guide

Part 2: Operational Amplifiers

Custom Search


An operational amplifier is a very high gain amplifier. Op amps can be used in many different ways. Two of the most common uses are

a) as comparators

b) as amplifiers (either NON-INVERTING or INVERTING amplifiers)

An op amp has TWO inputs; one non-inverting (called the "+" input) and one inverting (called the "-" input). The voltage at the output (Vo) depends on the DIFFERENCE between the voltage at the non-inverting input (V+) and the voltage at the inverting input (V-). Expressed mathematically,

Vo = A.(V+ - V-)

where A is the gain or voltage amplification of the op amp (typically 100000)

The diagram below shows an op amp together with its circuit symbol.


Op amp


circuit symbol

N.B. Op amps must, of course, always have a battery or some other supply of energy connected to them. However, in many circuit diagrams the supply connections are not drawn.

In the experiments which follow, use digital voltmeters.

Part 2 : Digital Electronics

Top of the Page

Privacy Policy

Sponsored Links

Sponsored Pages

Donating to the ODWS

Advertising on the ODWS


Electronics Homepage

The Open Door Team
Any questions or problems regarding this site should be addressed to the webmaster

David Hoult 2017