A DC Regulated power supply (25V) is an important part of today’s consumer electronics. It serves as an interface between a common wall outlet (230v/240v) & the circuitry of any electronic test equipment or device. So, In this project, we are going to design a 25V Regulated power supply circuit using an LM317T voltage regulator IC.
LM317T is a three-terminal voltage regulator IC, with a high output current value of 1.5A. The LM317 IC has many features such as current limiting, thermal protection, and safe operating area protection. It can also provide a float function for high voltage uses. If we disconnect the adjustable terminal still, LM317T will be helpful in overload protection.
Hardware Components
The following components are required to make a 25V Regulated Power Supply Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Stepdown Transformer | 230V/28V,50Hz | 1 |
| 2. | Voltage regulator IC | LM317T | 1 |
| 3. | Bridge rectifier Diode | 2A | 1 |
| 4. | Heat Sink | – | 1 |
| 5. | Resistor | 240Ω | 1 |
| 6. | Potentiometer | 4.7K | 1 |
| 7. | Electrolytic Capacitors | 2200μF/35V, 1μF | 1 |
| 8. | Breadboard | – | 1 |
| 9. | Ceramic Capacitor | 100nF | 1 |
LM317 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of LM317
25V Regulated Power Supply Circuit
Working Explanation
An input voltage of 230V is applied at the primary of a non-CT transformer which steps it down to 28V/2A through mutual induction of the primary & secondary windings while maintaining the frequency at 50Hz. After which the 28V AC signal goes through a bridge rectifier that converts the AC signal into a rippling DC signal.
The rectified voltage is then fed into the input of an adjustable voltage regulator LM317T. This three-terminal voltage regulator has an output voltage operating range from 1.2V to 37V DC with a maximum load current of up to 1.5A. The output voltage range is controlled by connecting a 4.7KΩ pot at the ADJ pin of the regulator. The DC signal then passes through a smoothing capacitor of 1μF before going on towards the output.
Applications
- DC power supplies are widely in use in low voltage applications such as charging batteries, automotive applications & aircraft applications.
