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Rojony Khatun Author
Rojony Khatun
CalculatorToolsProjectExpert
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MaΕ‚gorzata Koperska, MD Steven Wooding
Last updated: September 22, 2025

Multi-Volt Transformerless Power Supply Circuit Diagram

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4.7Β΅F 100V Capacitor

4.7Β΅F 100V Capacitor

A polarized electrolytic capacitor rated at 4.7 microfarads with a voltage capacity of 100 volts, used for smoothing, coupling, and decoupling in electronic circuits.

0.1Β΅F 400V Capacitor

0.1Β΅F 400V Capacitor

A non-polarized film/ceramic capacitor with 0.1 microfarad capacitance and 400V voltage rating

1N4007 Diode

1N4007 Diode

General-purpose 1000V, 1A diode

11V Zener Diode

12V Zener Diode

Voltage-regulating diode, 12V clamp

9V Zener Diode

9V Zener Diode

Voltage-regulating diode, 9V clamp

6V Zener Diode

6V Zener Diode

Voltage-regulating diode, 6V clamp

3V Zener Diode

3V Zener Diode

Voltage-regulating diode, 3V clamp

2.9R Fixed Resistor 2W

2.9R Fixed Resistor 2W

A 2.9-ohm resistor rated for 2 watts

22R Fixed Resistor 2W

22R Fixed Resistor 2W

A 22-ohm resistor rated for 2 watts

560K Fixed Resistor 1/4W

560K Fixed Resistor 1/4W

A 560,000-ohm resistor rated for 0.25 watts

[560k-fixed-resistor-1/4w]

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Multi-volt Transformerless Power Supply Circuit

Design a compact transformerless power supply circuit to get multiple DC voltages. Ideal for hobby electronics, small projects, and low-current applications.

transformerless power supply circuit

A multi-volt power supply is a transformerless power supply that converts AC mains into multiple DC voltages based on an active dropper, a rectifier, and zener diodes. It is small, economical, and suited to low current electronics.

low-current power supply project

The Multi-Volt Transformerless Power Supply Circuit is a simple circuit that will convert AC mains into various low-current DC voltages without the need to fit into a large transformer. In this form of power supply, capacitive dropping, diodes, zener diodes, and resistors are used to stabilize and control the voltages going out. A series capacitor is normally used to reduce the AC mains voltage to a safe level, then converted to DC through the use of diodes. That is, the necessary DC output voltage is provided by zener diodes or voltage regulators. Various devices can be used to get many outputs with varying zener diode ratings or regulator ICs. The circuit is very useful among the hobbyists, students and small electronics projects that need low-current multi-volt DC sources. Although it is small and inexpensive, it can only be used with low-power devices, LED circuits, and sensor modules because of isolation constraints. Mains AC should be properly isolated and guarded against when working.

Work / Installation (Inputs β†’ Outputs)

  • AC Input β†’ 220–240V AC mains.
  • Capacitive Dropper β†’ Series capacitor reduces AC voltage.
  • Rectification β†’ Diode bridge converts AC to pulsating DC.
  • Filtering β†’ Capacitors smooth DC output.
  • Voltage Regulation β†’ Zener diodes or regulators set desired output voltages.
  • Multiple DC Outputs β†’ Provide different voltages for LEDs, sensors, or small circuits.
  • Installation β†’ Assemble components on PCB, ensure proper insulation, verify connections, and test with low-current loads.

Testing & Final Adjustments

Once assembled power the circuit with an isolation transformer to avoid accident. Check all DC outputs with a multimeter in order to have the right voltage levels. Also examine diodes and regulators, make sure that the capacitors used do not overheat and that the polarity is correct. Tune voltages by adjusting zener diode values or resistor values. Check load stability by attaching low current loads such as LEDs or sensors. Make sure it is well insulated, there are no exposed connections of A, C, and that proper handling measures are in place. This will ensure a small, low-cost, and dependable multi-volt power supply applicable to hobby and educational-level electronics projects.

Frequently Asked Questions - Multi-volt Transformerless Power Supply Circuit:

What is a transformerless power supply?

A circuit converting AC to DC without using a bulky transformer.

Can it provide multiple voltages?

Yes, by using different zener diodes or voltage regulators.

Is it safe for high-power devices?

No, suitable only for low-current devices.

What is a capacitive dropper?

A capacitor used to reduce AC voltage safely for low-current circuits.

Do I need a fuse?

Yes, for safety against short circuits and overloads.

Can I use it for LEDs?

Yes, ideal for low-current LED circuits.

Is isolation needed?

Yes, proper insulation is critical to avoid electric shock.

How to regulate voltage?

Use zener diodes or voltage regulator ICs.

Is it beginner-friendly?

Yes, but safety precautions with AC are essential.

Applications?

Low-power electronics, sensor modules, LED circuits, hobby projects.

Rojony Khatun

Rojony Khatun

CalculatorToolsProject

Rojony Khatun is the creator of a free online tools website designed to simplify everyday and engineering-related calculations for students, professionals, and hobbyists. The platform offers a wide variety of basic and advanced calculators across key categories, including Electrical Calculators, Electronic Calculators, and Time & Date Calculators, helping users solve problems quickly and accurately.