Voltage Multiplier | Half Wave Voltage Doubler

What is Voltage Multiplier ?

With a diode, we can build a rectifier to produce a d.c. voltage that is nearly equal to the peak value
of input a.c. voltage. We can also use diodes and capacitors to build a circuit that will provide a d.c output that is multiple of the peak input a.c. voltage. Such a circuit is called a voltage multiplier. For example, a voltage doubler will provide a d.c. output that is twice the peak input a.c. voltage, a voltage tripler will provide a d.c. output that is three times the peak input a.c. voltage and so on. While voltage multipliers provide d.c. output that is much greater than the peak input a.c. voltage, there is no power amplification and law of conservation of energy holds good. When a voltage multiplier increases the peak input voltage by a factor n, the peak input current is decreased by approximately the same factor. Thus the actual power output from a voltage multiplier will never be greater than the input power. In fact, there are losses in the circuit (e.g. in diodes, capacitors etc.) so that the output power will actually be less than the input power.

What is Half-Wave Voltage Doubler ?

A half-wave voltage doubler consists of two diodes and two capacitors connected in a manner as
shown in Fig. 6.48. It will be shown that if the peak input a.c. voltage is VS(pk), the d.c. output voltage will be 2 VS (pk) provided the diodes are ideal (this assumption is fairly reasonable). The basic idea in a voltage multiplier is to charge each capacitor to the peak input a.c. voltage and to arrange the capacitors so that their stored voltages will add.

Half wave voltage doubler

Circuit action. We now discuss the working of a half-wave voltage doubler.
(i) During the negative half-cycle of a.c. input voltage [See Fig. 6.49 (i)], diode D1 is forward biased and diode D2 is reverse biased [See Fig. 6.49 (i)]. Therefore, diode D1 can be represented by a short and diode D2 as an open. The equivalent circuit then becomes as shown in Fig. 6.49 (ii).

Half wave voltage doubler circuit

As you can see [See Fig.6.49 (ii)], C1 will charge until voltage across it becomes equal to peak value of source voltage [VS (pk)]. At the same time, C2 will be in the process of discharging through the load RL (The source of this charge on C2 will be explained in a moment). Note that in all figures electron flow is shown.

(ii) When the polarity of the input a.c. voltage reverses (i.e. during positive half-cycle), the circuit conditions become as shown in Fig. 6.50 (i). Now D1 is reverse biased and D2 is forward biased and the equivalent circuit becomes as shown in Fig. 6.50 (ii).

working of voltage multiplier

Referring to Fig. 6.50 (ii), it is easy to see that C1 (charged to VS (pk) )and the source voltage (VS) now act as series-aiding voltage sources. Thus C2 will be charged to the sum of the series peak voltages i.e. 2 VS(pk)
(iii) When VS returns to its original polarity (i.e. negative half-cycle), D2 is again turned off (i.e. reverse biased). With D2 turned off, the only discharge path for C2 is through the load resistance RL. The time constant (= RL C2) of this circuit is so adjusted that C2 has little time to lose any of its charge before the input polarity reverses again. During the positive half-cycle, D2 is turned on and C2 recharges until voltage across it is again equal to 2 VS (pk).

∴ D.C. output voltage, Vdc = 2 VS (pk)

Since C2 barely discharges between input cycles, the output waveform of the half-wave voltage doubler closely resembles that of a filtered half-wave rectifier. Fig. 6.51 shows the input and output
waveforms for a half-wave voltage doubler.

output of multiplier

The voltage multipliers have the disadvantage of poor voltage regulation. This means that d.c. output voltage drops considerably as the load current increases. Large filter capacitors are needed to help maintain the output voltage.

Click Here to Download Whatwho App

Mcqs of Electronics | Energy band | Silicon  ( WhatsWho.com ) Learn Engineering Basics & Principles

Gas Filled Tubes | Conduction in a Gas ( Voltage Multiplier | Half Wave Voltage Doubler )

Half Wave rectifier | Properties | Frequency| Ripples ( Voltage Multiplier | Half Wave Voltage Doubler )

Diode | Types | Properties | Applications ( Voltage Multiplier | Half Wave Voltage Doubler )

Chapter Review Topics |Problems |Discussion Questions ( Voltage Multiplier | Half Wave Voltage Doubler )

MCQ’s| Electrons|Atomic | Voltage |Thevenin’s ( Voltage Multiplier | Half Wave Voltage Doubler )

Maximum Power Transfer Theorem |Applications ( Voltage Multiplier | Half Wave Voltage Doubler )

Thevenin’s Theorem | Properties | Problems ( Voltage Multiplier | Half Wave Voltage Doubler )

  1. CLICK HERE TO READ RELATED ARTICALS ( Voltage Multiplier | Half Wave Voltage Doubler )

2). CLICK HERE TO READ RELATED ARTICALS ( Voltage Multiplier | Half Wave Voltage Doubler )

3) CLICK HERE TO READ RELATED ARTICALS ( Voltage Multiplier | Half Wave Voltage Doubler )

4) CLICK HERE TO READ RELATED ARTICALS ( Voltage Multiplier | Half Wave Voltage Doubler )

Reference: Principles Of Electronics By V K Mehta And Rohit Mehta

3 thoughts on “Voltage Multiplier | Half Wave Voltage Doubler”

  1. The self education industry is a $355 Million per day industry and is expected to TRIPLE in the next 5 years! And with the right strategy this could be your opportunity to:

    Get in early before it is oversaturated.
    Help others go faster while you get paid
    Fix a broken system
    Make an impact on the world
    Get paid for a skill, hobby, passion or expertise you already have (or get paid from someone else’s)

    And Tony Robbins, Russell Brunson and Dean Graziosi are finally going to show YOU how to take advantage of it…

    (Now if you don’t already know who these 3 guys are then you’ll want to listen up!! They’ve impacted millions of lives and have generated billions of dollars)

    Look, if you’ve ever thought about (or even if you never thought about) getting paid for something you know (like a passion or a skill)… or even getting paid from what others know, then you have to attend.

    This is one of the fastest growing industries online and in all areas of the world.

    And for the first time ever they’re doing a webclass training on how to extract your wisdom (or somebody else’s) and get other people to pay you for it!

    You can save your spot here (and when you do register, you’re immediately going to get a brand new, never before seen training from Tony and Dean. No one else will ever get a chance to see this rare training except for us).


    After hearing what they’re teaching, I truly believe this is the #1 way to make a massive income, make a massive impact on the world and leave a legacy!

    And here’s just a fraction of what you’ll learn this week:

    The mostly hidden $129 Billion dollar market and how you can make a massive impact and leave a legacy by profiting from it.

    The KBB Triangle: The 3 ways to profit (whether you’re an expert with a thriving business, just getting started, or even if you’re at complete rock bottom)

    The framework to profit from what you (or someone else) already knows – or by creating community and bringing people together.

    Plus you’ll even be able to ask them questions when they do Q&A at the end of the training. (Chat is limited so show up early).

    There’s no other time where you’re going to have this opportunity. So BE THERE! Because if you’re not going to make a shift in your life now, then when? And if not with these guys, then let me ask with who?

    This is your rare chance to learn from 3 people who started from nothing and went on to generate billions of dollars and build massive companies.

    Spots are filling up faster than they ever have, so you need to hurry and go here to save your spot


    Register now and I’ll see you there this week – Plus they did a few brand new “pre-event” trainings that only those who register get access to.

    Talk soon


Leave a Reply

%d bloggers like this: