We saw that the DC output voltage being controlled by the rectifier is at a value below that of the mains input voltage. The Voltage Multiplier, however, is a special type of diode rectifier circuit which can potentially produce an output voltage many times greater than that of the applied input voltage.
Voltage multipliers are similar in many ways to rectifiers in that they convert AC-to-DC voltages for use in many electrical and electronic circuit applications such as in microwave ovens, strong electric field coils for cathode-ray tubes, electrostatic and high voltage test equipment, etc , where it is necessary to have a very high DC voltage generated from a relatively low AC supply.