Operational Amplifier Circuits

Nonlinear

Circuits

105

Unfortunately,

the

direct dependence

of the

output

on

temperature

remains.

Its

effect can

be

alleviated

by

means

of a

noninverting amplifier stage

(Figure

1-8) in

which

the

feedback network includes temperature-sensitive

elements

to

provide the required variation

of

gain with temperature.

It

can be

seen that

it is not

easy

to

design

a

logarithmic amplifier whose

accuracy will

be

maintained over

a

wide range

of

input voltages

and

tempera-

tures.

From

a

user's point

of

view

the

solution

is to use a

well-established cir-

cuit module,

of

which several

are

commercially available. These devices

are

often capable

of

inverse connectio ...