An electrical circuit known as a voltage doubler circuit uses input voltage to charge capacitors and then swaps these charges twice, producing twice as much voltage at the output as at the input.
In actuality, a traditional power supply generates an AC supply with a voltage of 230V that is suitable for a variety of electrical and electronic loads. However, some electronic devices, such as cathode ray tubes, X-ray machines, water pumps, lasers, travelling wave tubes, and so on, need a greater voltage in order to function. Therefore, the voltage multiplier device must be used to multiply the available voltage. With the help of capacitors and diodes, an electronics circuit known as a voltage multiplier, one can twice the applied voltage. Voltage multipliers come in a variety of forms, including double, triple, and quadruple multipliers.
What is a Voltage Doubler?
An electronic circuit that uses capacitors’ charging and discharging principles to twice the applied voltage is known as a voltage doubler circuit. It is made up of two primary electronic parts, such as diodes and capacitors.
Another way to describe it is as a rectifier that receives an AC input voltage and outputs a DC voltage that is almost twice as high as the input value. Despite the presence of a DC-to-DC voltage doubler, switching control in this kind of voltage doubler circuit requires a drive circuit.
Various circuits for voltage doublers are available, including basic voltage doublers, circuits based on 555 timers, voltage doubler rectifiers such as Villard and Greinacher circuits, bridge circuits, circuits with switched capacitors, Dickson charge pumps, and cross-coupled switched capacitors.
In this project, you will learn how to build a DC voltage doubler circuit with capacitors, diodes, and a basic 555 timer integrated circuit. The output of this circuit is double the input voltage while operating at a DC voltage of between 5 and 15 volts. For instance, the output voltage will be roughly 10V if the input value is 5V.
It uses capacitors and resistors to create a square wave frequency of about 2 kHz. The signals are amplified by connecting a 100uF capacitor and the forward-biased diode D2. The diode D1 keeps the capacitor C3 from completely discharging.
- NE555 Timer IC
- 1N4007 PN Diode (2x)
- 1000μF/35V Capacitor
- 100μF/35V Capacitor (2x)
- 0.01μF Ceramic Capacitor (Code: 103)
- Resistor (4.7KΩ, 2.2KΩ, 10KΩ)
- Red LED
The power supply’s positive connection is (+), and its negative connection is (-). Here, the 555 timer functions in an astable mode. We connect a 1000μF/35V capacitor between the input’s (+ve) and (-ve) terminals to smooth and stabilise the power supply. Attach pin 1 straight to the ground and pins 4 and 8 to (+ve).
Attach a 4.7KΩ resistor between pin 7 of the 555 timer IC and the (+ve). Additionally, attach a 10KΩ resistor to pins 7 and 6. As a result, connect pins 2 and 6 to ground via a ceramic capacitor with a 0.01μF value.
Attach a 100μF/35V capacitor to the output pin 3 of the 555 timer integrated circuit at the output section. Connect the capacitor’s (+ve) terminal to the series connection of two 1N4007 diodes as a result. This additional 100μF/35V capacitor is utilised to filter the voltage output.
Working Principle of Voltage Doubler Circuit
When the 100μF capacitor and 555 timer IC are combined, the output of the circuit generates a square wave. When a signal has a square wave frequency, it alternates between positive and negative voltage continually. For instance, the output voltage of a 555 timer IC will be 0V for a while if the input voltage is 5V. Next, adjust to 6V, hold it there for a while, then adjust to 0V once more, and so forth. We incorporated a 100μF capacitor, connecting its negative terminal to the 555 timer’s output and connecting its positive terminal via a diode to the positive terminal.
A 100μF capacitor must be added, with its positive terminal linked via a diode to the positive terminal of the 555 timer and its negative terminal connected to the output of the timer.
The arrangement’s reasoning is that the 100μF capacitor charges through the 1N4007 diode when the 555 timer ic output is at 0V (-ve). The applied voltage equals the voltage that the capacitor receives when it is charged. It indicates that the diode’s forward bias voltage is almost equivalent to the applied voltage’s positive voltage. When the 555 timer ic’s output is at (+ve), the voltage across the 100μF capacitor will be connected in series with the 555 timer ic’s output.
The voltage across the capacitor plus the voltage at the 555 timer IC’s output equals the voltage of the 100μF capacitor, however, because two voltage sources are connected in series. Furthermore, the voltage across the 100μF capacitor and the output voltage of the 555 timer IC equals the power supply’s (+ve) voltage. The voltage at the end will be twice that of the input. No current flows back to the positive terminal of the diode because the voltage at the n-junction is greater than the voltage at the p-junction.
We currently have two times the input voltage. To stop the output current from passing through the capacitor, another 1N4007 p-n diode is added. To filter the output, a 100μF capacitor is attached at the end.
Applications of Voltage Doubler Circuit
- Testing of Electronic Components: In research facilities, voltage doublers are used to test electronic components at greater voltages without requiring an external power source.
- High-Voltage Power Supplies: Voltage doublers help to produce high-voltage power supplies that are utilised in industrial machinery, medical equipment (X-ray machine’s), and particle accelerators, among other applications.
- DC-DC Voltage Boosting: Voltage doublers can be used in battery-powered devices to raise the voltage level, effectively boosting the lower battery voltage and increasing the device’s operating time.
- Photomultiplier Tubes: These are sensitive light detectors found in a variety of scientific instruments, including spectrometers and night vision devices. Voltage doublers are frequently employed in the power supply circuits of photomultiplier tubes.
- Capacitor Voltage Multipliers: Capacitor voltage multipliers, which are used in high-voltage physics experiments, specialised power supply, and pulse power systems, use voltage doublers.