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Rojony Khatun Author
Rojony Khatun
CalculatorToolsProjectExpert
Reviewers
Małgorzata Koperska, MD Steven Wooding
Last updated: September 21, 2025

DIY AC to DC Power Supply Circuit for Electronics Projects

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1000µF Capacitor

1000µF Capacitor

Large electrolytic capacitor with 1000 microfarads

1K Fixed Resistor 1/4W

1K Fixed Resistor 1/4W

A 1,000-ohm resistor rated for 0.25 watts

3V LED 5mm

3V LED 5mm

3V, 5mm round light-emitting diode

1N4007 Diode

1N4007 Diode

General-purpose 1000V, 1A diode

12V Transformer

12V Transformer

Step-down transformer converting 220V AC to 12V AC

LM7812 Voltage Regulator

LM7812 Voltage Regulator

Fixed positive voltage regulator (commonly 5V, 12V, 15V)

[lm7812-voltage-regulator]

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Convert AC to DC Power Supply

Convert AC mains voltage to stable DC with this DIY power supply circuit. Ideal for hobby electronics, microcontrollers, and small devices requiring a regulated DC output.

AC to DC power supply DIY

A DIY power supply circuit is an AC to DC power supply circuit that converts high voltage AC mains to low voltage DC that can be used in electronics projects. It has a smooth and safe DC output with the help of a transformer, rectifier, and capacitor.

bridge rectifier power supply

The DIY AC to DC Power Supply Circuit is a project aimed at converting the alternating current (AC) on the mains into a stable direct current (DC) voltage, which can then be used on electronic projects. The simple circuit comprises a step-down transformer, a bridge rectifier (diodes), a filter capacitor, and a voltage regulator, which is optional, so as to provide a smooth DC output. The high AC voltage is lowered by the transformer to a lower value. The bridge rectifier makes AC into pulsating DC and the capacitor filter eliminates ripples. To get an accurate voltage output, an adjustable LM317 or a regulator IC (such as 7805, 7812, or adjustable) may be used. The circuit is suited to introduction to electronics projects, microcontroller projects, battery charging, and battery powering of small devices. When dealing with mains AC voltage, proper fuses, safety measures, and insulation should be in use.

Work / Installation (Inputs → Outputs)

  • AC Input → Mains supply (e.g., 220V AC).
  • Step-down Transformer → Reduces voltage to desired level.
  • Bridge Rectifier → Converts AC to pulsating DC.
  • Filter Capacitor → Smooths voltage ripples.
  • Voltage Regulator (Optional) → Provides stable DC output.
  • Output → Usable DC voltage for electronic devices.
  • Installation → Assemble on PCB/enclosure; use fuses and insulation for safety.

Testing & Final Adjustments

Once assembled, be careful when connecting the AC input and measure the DC output using a multimeter. Make sure that the output voltage is within the envisaged range. Raise adjustor (when necessary) to fine voltage. Positioning of check capacitors and connection of diodes to avoid failures. Load test using a small device or resistor to ensure stability and ripple reduction. Make sure that there is no overheating of the transformer, diodes, or regulator. Proper insulation and fuse protection should be used to avoid short circuiting or electric shock. Last testing produces a safe, stable and efficient AC to DC power supply that would be used in a hobby, microcontroller or small electronics project.

Frequently Asked Questions - Convert AC to DC Power Supply:

What is the purpose of this circuit?

To convert AC mains voltage to stable DC voltage for electronics projects.

Can I use it for microcontrollers?

Yes, suitable for 5V, 9V, or 12V DC microcontroller projects.

Do I need a transformer?

Yes, to step down AC voltage to a safe level.

Is a voltage regulator necessary?

Optional, but recommended for stable DC output.

Can I use it to charge batteries?

Yes, depending on the voltage and current rating.

Is it beginner-friendly?

Yes, basic knowledge of electronics is sufficient.

Do I need safety precautions?

Yes, handle AC voltage carefully with fuses and insulation.

What components are critical?

Transformer, bridge rectifier, capacitor, and regulator IC.

Can it supply multiple devices?

Yes, within the current rating of transformer and regulator.

Is it cost-effective?

Yes, uses readily available and inexpensive components.

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.