How waveform of halfwave and fullwave single phase rectifier is formed?

Answer 1

The diode conducts during only one half-cycle, 8.333ms. To build a power supply you add a capacitor, which will charge up to the peak voltage of 170V. (Scale all of this if you are using a transformer.) Once you add (constant) load the voltage will change into a 60Hz sawtooth. The diode will conduct until the peak at which it becomes reverse-biased and the capacitor carries the load. The voltage will slope down linearly (assuming constant current load) until it intersects the rising AC voltage about 8ms later, and the diode conducts, carries the capacitor over the peak, and the process starts over. You have to decide if this amount of ripple is OK. You are probably using a regulator stage next, but you must consider the power dissipation by the regulator. If you go full-wave, the diodes alternately conduct during both cycles. The sawtooth will still be there, but the time from one peak reverse-bias to the next intercept and forward-bias is cut substantially, with the waveform at 120hz. This cuts ripple peak-peak voltage, and allows you to use a smaller capacitor and/or decrease the headroom allowing the regulator to run cooler.