Simple Positive (+) to Negative (-) Voltage Inverter Circuit

This is a simple circuit that can be used to convert the positive input voltage become negative voltage. Here’s the figure of the circuit;

Component list:

Part    Total Qty.    Description          
R1    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         

In this circuit, 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. For better regulation, a 79LOxx series regulator can be used. A zener diode may also be used to regulate the output voltage.