Table of Contents
Introduction
This 5V 1A power supply circuit is a reliable and efficient solution for powering low-voltage electronic devices such as microcontrollers, sensors, and other digital circuits. It converts standard 230V AC mains voltage into a stable 5V DC output using a step-down transformer, bridge rectifier, smoothing capacitors, and a 7805 voltage regulator IC. The transformer reduces the high AC voltage to a safer 9V AC, which is then rectified by four 1N4007 diodes. The resulting DC is filtered using electrolytic and ceramic capacitors to eliminate ripples and noise. The 7805 regulator ensures a constant 5V output with a current capacity of up to 1 ampere. This simple and cost-effective design is ideal for beginners and hobbyists looking to build a regulated DC power supply for their electronic projects.
Components Required
| S.No | Component Name | Value | Quantity |
|---|---|---|---|
| 1 | Transformer (TR1) | 230V AC to 9V AC | 1 |
| 2 | Diode | 1N4007 | 4 |
| 3 | Capacitor (Electrolytic) | 2200µF / 35V | 1 |
| 4 | Capacitor (Polyester) | 330nF | 1 |
| 5 | Voltage Regulator IC | 7805 | 1 |
| 6 | Capacitor (Ceramic) | 100nF | 1 |
| 7 | Capacitor (Electrolytic) | 100µF / 25V | 1 |
| 8 | Heat Sink (Optional) | Suitable for 7805 | 1 |
LM7805 Pinout
Circuit Diagram
Circuit Explanation
1. Input:
- 230V ACMains AC supply (230V AC) is connected to the primary coil of the transformer (TR1).
2. Transformer (TR1)
- The transformer steps down the 230V AC to 9V AC at 1A.This is a safer, lower voltage suitable for conversion to DC.
3. Bridge Rectifier
- Four 1N4007 diodes are arranged in a bridge configuration to convert the AC voltage to pulsating DC.This setup ensures full-wave rectification, improving efficiency.
4. Smoothing Capacitor (C1)
- C1 (2200µF, 35V) smooths the pulsating DC into a more stable DC voltage.This large capacitor filters out most of the AC ripple.
5. Decoupling Capacitor (C2)
- C2 (330nF) is a bypass capacitor that helps remove high-frequency noise from the power line before it enters the regulator.
6. Voltage Regulator (IC 7805)
- The 7805 voltage regulator IC regulates the input voltage (which may be ~12V DC) to a constant 5V DC output.It can supply up to 1A of current.A heatsink is recommended as the IC can get hot during operation.
7. Output Capacitors (C3 and C4)
- C3 (100nF): A ceramic capacitor to reduce high-frequency noise at the output.C4 (100µF, 25V): An electrolytic capacitor for additional smoothing and stability at the output.
8. Output
- You get a regulated +5V DC output at up to 1A, suitable for powering microcontrollers like Arduino, sensors, and small modules.
Applications
- Arduino and other microcontroller projects
- Sensor modules and breakout boards
- USB device chargers
- Wi-Fi modules like ESP8266/ESP32
