Friday, March 23, 2012 by skemarangkaian
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 .
IC2 is 7912 negative regulator and its pins are slightly different from 7812. See the connection in the diagram. 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.