Last Updated on March 31, 2024
Automatic solar powered LED light can be used for Garden, outdoor, farm etc… this circuit constructed with 6V solar panel and 12 high bright white LEDs. You can use 6V/4Ah SLA battery this will get charged during day time though the solar panel power and during night time this battery acts as power source for LEDs.
The LDR placed in this circuit drives LED as off during day time and on during night time with the help of SL100 switching transistor.
Components List
| S.No | Name | Quantity |
| 1. | Solar panel 6V | 1 |
| 2. | Regulator IC 7806 | 1 |
| 3. | Diode 1N4007 | 1 |
| 4. | LED white | 12 |
| 5. | LDR (photocell) | 1 |
| 6. | Resistor 1Ω/5watts Resistor 1KΩ Variable resistor 50KΩ preset | 1 1 1 |
| 7. | Transistor SL100 | each 1 |
| 8. | Capacitor 470µF/25V 0.1µF | each 1 |
As you can see this simple circuit uses solar power to charge the Battery and the LED light array is connected with Switching transistor SL100, you can use TIP31C (NPN) transistor if SL100 not available, This transistor Base terminal is connected with LDR. Whenever the light falls on LDR, it give low resistance to Current flow so the current through R2 and variable Resistor R3 quickly Grounded without allowing it to reach transistor base, so there is no base current and hence the transistor stay is cutoff region.
When the sun light intensity decreased or night comes the LDR won’t receive enough light so it gives Very high Resistance to current flow. So the current flow from R2 and Variable Resistor R3 reaches base terminal of transistor easily, so the transistor gets turn ON and makes LED array Glow.
Note: Keep LDR to opposite direction to LED Light array and make sure that, Sun light fall on LDR during day time.