All You Need to Know About Voltage Multipliers
A voltage multiplier is a device that converts low AC voltage to higher DC voltage. It's based on increasing the number of capacitors and diodes in a circuit. The device is often used for safety tests. Voltage multipliers can increase voltage up to seven times.
Role of Voltage Multiplier Sometimes it's impractical to house huge transformers at a facility due to size and cost. Voltage multiplier circuits serve as an affordable alternative, since they only involve adding diodes and capacitors to increase voltage. Like rectifier circuits, voltage multiplier circuits covert AC to DC, except that they can produce very high DC voltage. Here are the different types of voltage multipliers:
- Full wave voltage doubler
- Half wave voltage doubler circuit
- Voltage tripler circuit
- Voltage quadruple circuit
Full Wave Voltage Doubler The input voltage is doubled. In the positive half cycle of the AC wave, one diode is forward biased while a second diode is reverse biased. The capacitor charges through the first diode to the peak value (Vpeak) of the sine wave. During the negative half cycles, the roles switch, as the first diode becomes reverse biased while the second diode becomes forward biased.
Half Wave Voltage Doubler Circuit Diode D1 is forward biased in the first positive half cycle, while the capacitor gets charged to Vpeak. During the negative half cycle, a second diode acts as a conductor while D1 prevents the discharging of the capacitor, reaching Vpeak. That means the capacitor is charged to 2Vpeak. Ultimately, the capacitor is charged in one cycle, which is followed by a discharge cycle.
Voltage Tripler Circuit This circuit is created by adding a third diode and capacitor to a half wave voltage doubler circuit. During the second positive half cycle, two diodes conduct while one diode has a reverse bias. One capacitor charges another up to 2Vpeak.
Voltage Quadruple Circuit Increasing a diode in a voltage tripler circuit results in a voltage quadruple circuit, in which four times the Vpeak is achieved. The problem with using this type of circuit is output can be difficult to manage due to high ripple frequency.