Wednesday, July 2, 2008

Power supply circuit

Designing a power supply circuit is one of the basic steps in any projects which you are about to start. Now let us see a +5 volt regulated power supply circuit, which i have used for my project. The circuit diagram is shown below.

The circuit includes a step down transformer and a full wave rectifier followed by a +5 volt regulator. The step down transformer steps down the ac voltage from 230 volts to 12 volt ac. After that it is passed through a full wave rectifier where we obtain an unregulated dc supply of 12 volt. The dc supply is regulated by passing through the regulator 7805. The capacitors are used to avoid ripples in the incoming voltage. The photo below shows my +5volt power supply circuit.

Note that i have included a RED LED to indicate whether the power supply is ON or OFF. I have provided a Heat sink to 7805 inorder to withdraw maximum amount of current from it. Without Heat sink we can draw current only upto 150mA.

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