The circuit is use to regulation dual power supply that provides +12V and -12V from the AC mains. A power supply like this is a very essential tool on the work bench of an electronic hobbyist. This is the figure of the schematic of the circuit.
This circuit is built by LM7812 and LM7912 for the voltage regulator IC. The transformer T1 steps down the AC mains voltage and diodes D1, D2, D3 and D4 does the job of rectification. Capacitors C1 and C2 does the job of filtering.C3, C4, C7and C8 are decoupling capacitors. IC 7812 and 7912 are used for the purpose of voltage regulation in which the former is a positive 12V regulator and later is a negative 12V regulator. The output of 7812 will be +12V and that of 7912 will be -12V. Transformer T1 can be a 230V primary; 15-0-15 V, 1A secondary step-down transformer. Fuse F1 can be a 500mA fuse. Capacitor C1, C2, C5 and C6 must be rated at least 50V.
This circuit is built by LM7812 and LM7912 for the voltage regulator IC. The transformer T1 steps down the AC mains voltage and diodes D1, D2, D3 and D4 does the job of rectification. Capacitors C1 and C2 does the job of filtering.C3, C4, C7and C8 are decoupling capacitors. IC 7812 and 7912 are used for the purpose of voltage regulation in which the former is a positive 12V regulator and later is a negative 12V regulator. The output of 7812 will be +12V and that of 7912 will be -12V. Transformer T1 can be a 230V primary; 15-0-15 V, 1A secondary step-down transformer. Fuse F1 can be a 500mA fuse. Capacitor C1, C2, C5 and C6 must be rated at least 50V.
