Would you like to know how to build your own 12V Solar LED Night Lamp? These low-cost LED Lamps are a great low-cost solution for lowering your energy cost. They can be easily made at home by combining a simple solar power battery with an LDR-operated lamp circuit. They are cheap, reliable & require low maintenance. So, in this project, we’re going to build a 12V Solar LED Night Activated Lamp Using LM317T voltage regulator IC.
The LM317T is a three-terminal voltage regulator IC, with a high output current value of 1.5A. The LM317T 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 Required
You will need the following parts to build this project
| S.no | Components | Value | Qty |
|---|---|---|---|
| 1. | Solar Panel | 18V | 1 |
| 2. | regulator IC | LM317T | 1 |
| 3. | LDR | – | 1 |
| 4. | LEDs (White) | 18x5mm | 1 |
| 5. | Diode | 1N4001 | 1 |
| 6. | NPN transistor | BC548 | 1 |
| 7. | NPN transistor | 2N2222 | 1 |
| 8. | Potentiometers | 50K, 1K | 1 |
| 9. | Capacitor | 0.22uF | 1 |
| 10. | Resistors | 1K, 470Ohms, 120 Ohms, 100Ohms, 0.5Ohms/6W, 56 Ohms | 1 |
| 11. | Breadboard | – | 1 |
| 12. | Connecting Wires | – | – |
| Pin No. | Pin Name | Description |
|---|---|---|
| 1 | ADJ | Adjust Vout by connecting a resistor to a divider circuit. |
| 2 | OUT | Output voltage pin (Vout) |
| 3 | IN | Input voltage pin (Vin) |
Circuit Diagram
Working Explanation
The operation of the circuit can be broken down into two stages. During the day, in the first stage, the Solar panels send an 18V input to LM317T IC. The ADJ pin of the IC is connected to the collector of a BC548 transistor, which regulates the output of the IC as per the charging level of the battery. The 12V output from the IC charges the 12V battery.
The second consists of a simple LDR lamp circuit with a 12V battery as its power source. As night falls, the LDR resistance goes low and the 12V DC signal from the battery acts as a control signal to the base of the 2N2222 transistor. This switches on the transistor and connects the collector output to the LEDs which then light up.
Applications
- It usually serves as an emergency backup power in case of severe power outages.
- They also help to reduce electricity bills.
- They can be used in common hobbies such as gardening, backyard work, etc.
