Category: Main page Power Circuits

Source:
http://www.aaroncake.net/

This simple circuit is a good solution to the powering a dual supply op amp from a single battery problem. The circuit simply takes a positive voltage and inverts it. It uses only one 555 timer and a few other passive components, so it doesn't add much in the way of size and cost to a project.

## Schematic

## Parts

Part

Total Qty.

Description

SubstitutionsR1

1

24K 1/4 Watt Resistor

R2

1

56K 1/4 Watt Resistor

C1

1

3300pF 25V Ceramic Capacitor

C2

1

47uF 25V Electrolytic Capacitor

C3

1

10uF 25V Electrolytic Capacitor

D1, D2

2

1N4148 Silicon Diode

U1

1

555 Timer

MISC

1

Wire, Board

## Notes

1. V+ can be anywhere from 4 to 16V. -V is one volt less than V+. So for -12V output, use +13V input. The maximum current output of the circuit is about 280mA, more than enough for a few op amps.

2. For better regulation, a 79LO

xxseries regulator can be used.3. A zener diode may also be used to regualte the output voltage.