Circuit diagrams and schematics - Electronic projects

Here is circuit 9V power supply regulator with battery 12V backup system. Use IC 7812 and 7805 control voltage output by R3 1K output 9V 1A max. This is a 9V power supply which will work even on power failure. It uses a rechargeable battery and regulators. A transformer with 15-0-15 AC volts output is [...]

This circuit is a simple form of the commercial UPS, the circuit provides a constant regulated 5 Volt output and an unregulated 12 Volt supply. In the event of electrical supply line failure the battery takes over, with no spikes on the regulated supply. This circuit can be adapted for other regulated and unregulated voltages [...]