Operational Amplifier Circuits

Preface

The operational amplifier

is

essentially

an

electronic circuit capable

of

producing

an

output that

is

related

to its

input

by a

known mathematical operation. Originally

such circuits were cumbersome

and

expensive, since they made

use of

several

thermionic vacuum tubes and, subsequently, discrete transistors. Today

"op

amps,"

as they have become known popularly,

are

available

as

integrated circuit "chips"

at

very

low

cost. Four chips, costing twenty cents

or

less each,

can be

accommodated

in

one

small package. Consequently chips

are

used

in a

remarkably wide range

of

applications,

not all of

which

are

directly related

to the

origina