Multiplier for Voltage In electrical engineering, circuits are crucial parts that offer a way to increase the voltage levels of different applications. Power supplies and other electrical devices are only two of the many applications for these circuits. Engineers should be aware of their various uses and functioning principles because they are crucial to the electronics industry. We observed in the rectifier lesson that the rectifier's controlled DC output voltage is lower than the mains input voltage. However, the voltage multiplier is a unique kind of diode rectifier circuit that has the ability to generate an output voltage that is several times higher than the applied input voltage. A suitable step-up transformer or a specifically insulated transformer needed for high-voltage applications may not always be accessible, even though using a voltage transformer to raise a voltage is common in electronic circuits. Using a diode voltage multiplier circuit, which raises or "steps-up" the voltage without the need of a transformer, is an alternate method.
What is a Voltage Multiplier?
An electronic circuit made up of capacitors and diodes is
called a voltage multiplier, and it is used to increase or multiply the voltage
of an AC signal. An AC voltage of lesser value is sent into the voltage
multiplier, which transforms it into a DC voltage and raises the voltage level.
As a result, a voltage multiplier circuit can multiply voltage in addition to
rectifying it. In this case, the capacitors raise the voltage while the diodes
carry out the rectification process.
Types of Voltage Multiplier Circuits
Voltage multiplier circuits come in four different
varieties, which are as follows:
- Voltage Doubler
- Voltage Tripler
- Voltage Quadrupler
There exist two kinds of voltage doubler circuits:
- Half-Wave Voltage Doubler and
- Full-Wave Voltage Doubler.
Two types of voltage doubler circuits are explained below:
Half-Wave Voltage Doubler
An electronic circuit known as a half-wave voltage doubler is used to double the voltage of an alternating current or signal. The components of this half-wave voltage doubler are a capacitor and a diode. The diode permits current to charge the capacitor to a high voltage during the positive half cycle of the AC input. The capacitor discharges via a load during the negative half cycle, doubling the voltage across the load, while the diode prevents the current from flowing. Although this circuit is generally simple, it is not as effective as other kinds of rectifiers.
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| Circuit Diagram of Half-Wave Doubler Source: www.geeksforgeeks.org |
Function of Half-Wave Voltage Doubler
The diode D1 conducts when it becomes forward biased during
the positive half cycle, charging C1 to its maximum input voltage. The charge
is transferred from C1 to C2 during the negative half cycle when diode D1 is
reverse biased and does not conduct, while diode D2 is forward biased and
conducts. The C2's output voltage (Vout) is roughly twice as high as its peak
input voltage.
Full-Wave Voltage Doubler
An electrical circuit designed to double the voltage of an alternating current or signal is called a full-wave voltage doubler. It functions as a bridge rectifier, which is made up of four diodes arranged so that the input signal's positive and negative half cycles are rectified. The process doubles the voltage across the load by charging the capacitor in both directions in both cycles. Compared to half-wave voltage doublers, which produce a clean DC output with a lower ripple factor, full-wave voltage doublers are more efficient.
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| Circuit Diagram of Full-Wave Doubler Source: www.geeksforgeeks.org |
Function of Full-Wave Voltage Doubler
Capacitor C1 charges as a result of diodes D1 and D2
becoming forward-biased and conducting during the positive half cycle. Diodes
D3 and D4 become forward biased during the negative half cycle, causing them to
conduct and double the voltage across the load (R). Taking into account both
half cycles, the output voltage (Vout) is roughly twice the peak input voltage.
Voltage Tripler
An electrical circuit known as a voltage tripler is designed to increase the voltage of an alternating current or signal by three times the input value. It achieves this kind of voltage multiplication by combining diodes and capacitors. During various AC signal cycles, this kind of circuit also features a sequence of charging and discharging cycles via capacitors. The voltage tripler generates an output voltage that is roughly three times the value of the input AC voltage when the components are connected correctly. Because a large DC voltage is needed, this kind of circuit is primarily utilized in high-voltage applications.
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| Circuit Diagram of Tripler Source: www.geeksforgeeks.org |
Working of Voltage Tripler
Voltage Quadrupler
An electrical circuit known as a voltage quadrupler is designed to increase the voltage of an alternating current or signal by four times its input value. To increase voltage, this circuit uses a mixture of capacitors and diodes. During various AC signal cycles, the capacitors go through cycles of charging and discharging. The quadrupler produces an output voltage that is roughly four times the value of the input signal if the components are connected correctly. This kind of circuit is primarily utilized in applications that require a high DC voltage. It also offers a straightforward and superior method of accomplishing voltage multiplication.
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| Circuit Diagram of Quadrupler Source: www.geeksforgeeks.org |
Working of Voltage Quadrupler
The capacitors C1 and C11 can be charged from the input
voltage because the diodes D1 and D11 become forward biased and conduct during
the positive half cycle. The capacitors C2 and C22 can charge to the input
voltage because the diodes D2 and D22 become forward biased and conduct during
the negative half cycle. Now, as the input voltage increases during the
subsequent positive half cycle, diodes D1 and D11 become reverse biased, and
the voltage between C1 and C11 doubles, hence doubling the voltage. In the same manner, diodes D2 and D22 reverse bias during the subsequent negative half
cycle, which doubles the voltage across C2 and C22. The voltage across the
capacitors doubles as a result of repeating this operation with positive and
negative half cycles. When everything is finished, the voltage across the load
is quadrupled because it is four times the input signal.
Advantages of Voltage Multiplier Circuit
- It improves compact design.
- For high voltage output, it is employed.
- Simple construction is one of its uses.
- Its low cost makes it useful.
- Its effectiveness in some applications is the reason it is employed.
Disadvantages of Voltage Multiplier Circuit
- It is restricted exclusively to low-power applications.
- Voltage ripple is the result.
- It is quite sensitive to changes in load.
- Its frequency range is limited.
- Its scaling for higher voltages is complex.
Applications of Voltage Multiplier Circuit
- Cathode Ray Tube (CRT) displays make use of it.
- In X-ray generators, it is utilized.
- Particle accelerators make use of it.
- High-voltage power supplies make use of it.
- Photomultiplier tubes make use of it.
Conclusion
In electrical and electronics engineering, voltage multiplier circuits—which include half-wave doublers, full-wave doublers, triplers, and quadruplers—are crucial. In various applications, these circuits effectively raise output voltages. These kinds have both advantages and disadvantages, but several advantages stand out, such as their small size, ease of use, and—above all—their higher output. Then, we learned that voltage multipliers are straightforward circuits composed of diodes and capacitors that can raise the input voltage by two, three, or four times. They can also be used to apply the desired DC voltage to a given load without the need for a step-up transformer by cascading individual half-stage or full-stage multipliers in series. Engineers frequently use these circuits in high-voltage applications and electrical power supply devices. The benefits of voltage multipliers make them the ideal instruments for designers looking for dependable, effective voltage multiplication solutions in complex engineering applications, even though they have certain drawbacks, including loading times and complexity.
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