In this tutorial, we will demonstrate the easiest DIY project with a simple and economical design. An 11V power supply using LM7811 IC. A power supply is an electrical device that converts a varying input voltage into a constant ‘regulated’ output voltage. The purpose of a power supply is to provide electric power to an electric load
LM7811 voltage regulator IC with a heat sink is deployed in this project. LM7811 is a 3 terminal, 1A voltage regulator IC of LM78xx series available in TO-220/D-PAK package with several fixed output voltages. The IC has many built-in features like internal current limiting, thermal shut-down, and safe area protection. If adequate heat sinking is provided, they can deliver over 1A output current. Although the LM78xx series is designed as fixed voltage regulators, these devices are also utilized with external components to obtain adjustable voltages and currents.
Required Hardware
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | IC | LM7811 | 1 |
| 2. | Center tapped transformer | 230V/15V 2A | 1 |
| 3. | Diodes | 1N4001 | 4 |
| 4. | Electrolytic capacitor | 2200µF | 1 |
| 5. | Ceramic Capacitor | 330nF, 100nF | 1, 1 |
LM7811 Pinout
Circuit Diagram
Circuit Operation
The AC transformer having a primary rating of 230V or 110 V and the center-tap coil rates about 15V and 2A, steps down the input AC sinusoidal voltage signal from 230V to 12V. The AC signal is then allowed to pass through the diode bridge, where the bridge rectifies the sinusoidal AC signal i.e. converts the sinusoidal AC signal into a DC signal.
The rectified DC signal is then passed to the electrolytic 2200uF capacitor and nonpolar 330nF capacitor which filters out the noise and other interrupting agents from the unidirectional DC signal. The unidirectional and filtered DC waveform is then allowed to pass through the LM7811 IC which regulates this input voltage and provides 11V DC output. Since the heat sink is already embedded in the LM7811 IC minimizes the heat generation in the circuit and helps in maintaining the nominal temperature of the circuit.
Applications and Uses
- Use to power small electrical loads
- Use as rectifiers i.e. AC to DC converters
- Use in short circuit protection
- Served brilliantly in scenarios where there are strict limitations in internal current flowing
- Overheating shutdown properties.
