Question

You are being asked to develop a smoke detector which can be plugged into a wall outlet. The smoke detector is supposed to be very inexpensive, and consumes only 1mW of power. If your are designing an AC-DC converter for this device, would you use a half-wave rectifier, or a full-wave rectifier. Justify your answer.

Answer 1

Half- wave rectifier, because the smoke detector consumes very less power (i.e, 1mW) and the output voltage of a half-wave converter is less than full-wave converter.As the power to the smoke detector is directly plugged from wall socket which is 230 volts AC voltage we need to reduce it because the smoke detector required only 1mW and the rectification efficiency of half wave rectifier is very low compared to full wave we preffered Half wave rectifer.

note: Out put current of Half wave rectifier contains higher order harmonics hence we need to use effective filters to reduce them.