Here is the standard symmetric power supply using the Positive and Negative Voltage regulator ICs. It can give +12 volt and – 12 volt DC with a common ground. This power supply is ideal to power amplifier circuits that require well regulated symmetrical power supply. It can give 1 ampere current to the circuit.
14-0-14 volt 1 Ampere step down transformer is used to drop 230 volt AC to 14 volt DC which is then rectified using the standard full wave bridge rectifier comprising D1 through D4. Smoothing capacitors C1 and C2 remove the ripples from low volt AC. Two regulator ICs are used to generate +12 volt and -12 volt DC. IC1 is 7812 positive regulator giving +12 volt regulated output .
Symmetric Power Supply Schematic
IC2 is 7912 negative regulator and its pins are slightly different from 7812. See the connection in the symmetric power supply schematic. Regulated outputs from the regulator ICs are available from pin 3 which can be used to power the circuit. Capacitors C3 and C4 act as noise filters to give clean DC.