ABSTRACT

Variable D.0 power supply O-30v is mostly needed in electronic circuit such as radios, computers, and televisions e.t.c. dry batteries and dry cells are ripple free and portable. However there voltages are very low and they are expensive, and need frequent replacement as compared to conventional D.0 power supply, it is advantageous to convert this alternating voltage to D.C. voltage. This is called rectification. The process involves passing a voltage of 230v through the primary input of 230v step-down transformer and the secondary output voltage is fed into the rectifier circuit to convert A.0 to pulsating D.C. voltage. Also this is passed into the filter circuit; this circuit removes fluctuations or ripple present in the output voltage, supplied by the rectifier circuit. Though no filter can indeed give an output voltage that is perfectly free from ripples like D.0 battery, but it will be very close. It also involves voltage regulator circuit to keep the terminal voltage of the D.C. voltage constant, even when AC. input voltage to the transformer varies, or load varies. The last stage is voltage divider which is to provide different D.0 voltages needed by different electronic circuit.