9

FN8157.1

September 15, 2005

Applications Information

Electronic digitally controlled potentiometers provide two powerful application advantages: (1) the variability and reliability of a

solid-state potentiometer, and (2) the flexibility of computer-based digital controls.

Basic Configurations of Electronic Potentiometers

Basic Circuits

I

Three terminal potentiometer;

variable voltage divider

Two terminal variable resistor;

variable current

Cascading Techniques

Buffered Reference Voltage

–

+

+5V

+V

–5V

OP-07

+V

+V

+V

X

(a)

(b)

Noninverting Amplifier

+

–

LM308A

Voltage Regulator

317

Offset Voltage Adjustment

+

–

100k

Ω

10k

Ω

10k

Ω

10k

Ω

-12V

+12V

TL072

Comparator with Hysteresis

+

–

LT311A

+5V

–5V

(for additional circuits see AN115)

X9015