DIY +5V Regulated Power Supply for Breadboard

In the world of electronics and DIY projects, having a reliable power supply is crucial. Whether you're working on Arduino, ESP32, or other battery-powered circuits, a stable 5V power source can make your life a lot easier. In this blog post, I'll walk you through the process of building a +5V regulated power supply using an LM7805 IC and two 3.7V lithium-ion batteries.

Why Use an LM7805?

The LM7805 is a popular voltage regulator IC that provides a constant 5V output from a higher voltage input. It's widely used due to its simplicity, reliability, and availability. By using the LM7805, you can ensure your circuits receive a steady 5V, which is essential for the proper functioning of many electronic components.

DIY 5V regulated power supply

Materials Needed

  1. LM7805 Voltage Regulator IC
  2. Two 3.7V Lithium-Ion Batteries
  3. Battery Holder for Two Batteries
  4. Switch
  5. Breadboard
  6. LED
  7. 270Ohm resistor
  8. Capacitors (0.33µF and 0.1µF)
  9. Wires

Step-by-Step Guide

LM7805 5V regulated power supply circuit diagram is shown below.+5V Regulated Power Supply for Breadboards

1. Setting Up the Batteries

First, you'll need to place the two 3.7V lithium-ion batteries into the battery holder. The combined voltage of these two batteries will be approximately 7.4V (3.7V each), which is a suitable input for the LM7805 voltage regulator.

2. Connecting the LM7805

Place the LM7805 IC on the breadboard. The IC has three pins:

  • Input (Pin 1): Connect the positive terminal of the battery holder via the switch(see circuit diagram).
  • Ground (Pin 2): Connect the negative terminal of the battery holder.
  • Output (Pin 3): Connect the terminals pins that goes into breadboard power supply rail. This pin will provide the regulated 5V output.

3. Adding Capacitors

To ensure smooth operation and reduce noise, add a 0.33µF capacitor between the input pin (Pin 1) and ground (Pin 2), and a 0.1µF capacitor between the output pin (Pin 3) and ground (Pin 2). These capacitors help stabilize the voltage and filter out any unwanted noise.

4. Powering Your Circuit

With the connections in place, you can now use the output pin of the LM7805 to power your Arduino, ESP32, or any other 5V battery-powered circuit. Simply connect the 5V output and ground to the appropriate power inputs of your project.

See the animation of this circuit.

Applications and Benefits

This +5V regulated power supply is highly versatile and can be used in various projects:

  • Arduino Projects: Ensure your microcontroller receives a stable 5V power supply for reliable operation.
  • ESP32 Projects: Power your Wi-Fi and Bluetooth-enabled projects without worrying about voltage fluctuations.
  • General Battery-Powered Circuits: Provide a consistent power source for sensors, motors, and other components. See for example how this diy +5V voltage regulator can be used in the arduino and bluetooth based RC car.

Using lithium-ion batteries makes this setup portable and rechargeable, adding to the convenience and flexibility of your projects. See also 3.7V lithium ion automatic battery charger and how automatic cutoff battery charger circuit works.


Building a +5V regulated power supply using an LM7805 IC and lithium-ion batteries is a simple yet effective way to ensure your electronic projects have a stable power source. Whether you're working on Arduino, ESP32, or other battery-powered circuits, this setup can enhance the reliability and performance of your projects.

By following these steps, you can create a dependable power supply that will serve you well in many of your electronic endeavors. If you have any questions or need further assistance, don't hesitate to reach out in the comments section.

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