# Voltage Multipliers: Voltage Doubler, Tripler and Quadrupler

Voltage multipliers are electronics circuit for increasing voltage peak without using a transformer by utilizing clamping action. Most common voltage multipliers are double, triple and quadruple.

## Half Wave Voltage Doubler:

The load drops voltage in the first half cycle and in the second half cycle the voltage level is doubled again that why it is called half-wave voltage doubler. The half-wave voltage doubler uses two diodes and two capacitors.

### Positive Half Cycle

During the positive half-cycle, the diode D1 is forward biased charge the capacitor C1 to the peak voltage of the supply Vs. Where the diode D2 is reverse biased and there is no charging current in capacitor C2.

Applying KVL to the loop

$V_{m}-V_{c1}-0.7=0$
$V_{m}=V_{c1}+0.7$
$V_{m} \approx V_{c1}$

### Negative Cycle:

For the negative half cycle, the diode D1 is reverse biased and no charging current flow through capacitor C1. Where the diode D2 is forward biased and the charging current will flow in capacitor C2. The charging current of capacitor C2 will follow the following loop.

Applying KVL at the loop will give us

$V_{m}-V_{c2}-0.7+V_{c1}=0$

As$V_{c1}\approx V_{m}$, by putting it into the equation

$V_{m}-V_{c2}-0.7+V_{s}=0$
$V_{c2}=V_{m}-0.7+V_{s}$

If the load is connected to the output, the capacitor C2 will discharge during the positive half cycle and then it will charge again in the upcoming negative cycle.

## Full wave Voltage Doubler:

In Full-wave voltage doubler circuit, the voltage level is maintained double in both half cycle. It uses two capacitor and two diodes with a slightly different configuration.

### Positive Half Cycle

During the positive half cycle, the diode D1 conducts and charge the capacitor C1 to the supply voltage. Where the diode D2 is reverse biased and no current flow through capacitor C2.

## Full wave Voltage Doubler:

### Negative half Cycle

During the negative half cycle the diode D1 is reverse biased and no current flow through capacitor C1. Moreover, the diode D2 is forward biased and the capacitor C2 charge to the supply voltage.

If no load is conned to the output terminals the voltage will be twice the input peak voltage. In the case of load connected, the voltage level of the capacitor C1 will drop below the input peak voltage during the negative half and capacitor C2 level will drop during the positive half cycle. Peak inverse voltage for both voltage doubler is 2Vm.

Voltage tripler and quadrupler are the extensions of voltage doubler and increase the voltage level three times and four times respectively. As per the demand, a capacitor and diode set can increase the voltage level.

## Conclusion:

• Voltage multipliers are electronics circuit to increase the voltage peak a few times
• Voltage Doubler, Tripler and Quadrupler increases voltage peaks two, three and four times respectively
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