Building a 5V Power Supply: A Step-by-Step Guide

A power supply is an essential component in any electronic circuit. It is responsible for converting AC voltage into a stable DC voltage that can power electronic devices. In this tutorial, we will guide you through the process of building a 5V power supply from scratch.

The following shows diy 5V power supply circuit diagram.

5V power supply
Step 1: Choosing the Transformer 

The first step in building a power supply is choosing the transformer. A transformer is a device that converts high voltage AC power into low voltage AC power. In our case, we need a 120V AC, 60Hz to 12V AC transformer, which we will use to step down the voltage.

Step 2: Building the Half-Wave Rectifier 

Next, we need to build a half-wave rectifier using a 1N4001 diode and a 1KOhm resistor. The half-wave rectifier converts the AC voltage into a pulsating DC voltage. The diode only allows current to flow in one direction, while the resistor limits the current flow to a safe level.

Step 3: Adding the Filter Capacitor 

The pulsating DC voltage from the half-wave rectifier still contains a lot of ripples. To remove these ripples, we need to add a filter capacitor. We have chosen a 1000uF capacitor, which will smooth out the DC voltage and make it stable. See also how to use Choke Input Filter.

Step 4: Adding the Voltage Regulator 

The last step is to add the voltage regulator. We have chosen a 7805 voltage regulator, which will regulate the DC voltage to a stable 5V. The voltage regulator has three pins: input, ground, and output. We connect the input pin to the filtered DC voltage, the ground pin to the ground, and the output pin to the load.

Applications of a 5V Power Supply

A 5V power supply has a wide range of applications. It can be used to power microcontrollers, NodeMCU(ESP8266) board, sensors, and other electronic devices that require a stable 5V DC voltage. Additionally, a 5V power supply can be used in DIY projects such as building your own Arduino or Raspberry Pi projects. It is also commonly used in prototyping and testing electronic circuits.


Building your own power supply can be a fun and rewarding experience. By understanding how each component works, you can customize the power supply to suit your specific needs. A 5V power supply is a versatile and essential tool for any electronics enthusiast or hobbyist. With this guide, you can build your own 5V power supply and explore its many applications.

In this power supply design we have used 7805 power regulator IC, but we can also use simpler voltage regular build with Zener voltage regulator.

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