Designing regulated power supply
A regulated power supply gives a DC output voltage that remains substantially constant even when the ac supply voltage or the dc load current changes. The system contains (i) a rectifier with filter, and (ii) a voltage regulator. The rectifier transforms the input alternating current (or voltage) into a direct current (or voltage). The output of the rectifier contains the fluctuating components of current (or voltage), called the ripple. The filter following the rectifier stage smoothens out the ripples.
Block diagram of Regulated power supply
The output of the filter can vary with the changes in the ac supply voltage or the load resistance. The voltage regulator tends to eliminate this fluctuation.