In areas like the staircase or porch of your home, lighting is required only for a short period at night. We often forget to switch off these lights, which results in considerable wastage of electricity. So here Automatic light switches are used for convenience, and safety, and to save money. Some light up for easy switching at night, some switch on and off automatically, some are timed and others dim. In most situations, you can easily install automatic light switches yourself. Here we design an Auto switch-off light circuit, it drives the AC lamp for up to a few seconds and turns off the lamp.
Hardware Required
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Bulb | 230 volt, 60W | 1 |
| 2. | 1 Amps Bridge Rectifier | – | 1 |
| 3. | TRIAC | MOC3041 | 1 |
| 4. | TRIAC | BT136 | 1 |
| 5. | Push Button | – | 1 |
| 6. | Zener Diode | 5.1V/5W | 1 |
| 7. | IC | NE555 Timer | 1 |
| 8. | Resistor | 330Ω,1MΩ | 2,1 |
| 9. | Capacitor | 470uF/25V,22uF/25V,0.01uF | 1,1,1 |
| 10. | Connecting Wires | – | – |
Circuit Diagram
Construction and Working
As we can see in the circuit, the 230 volts, 60W bulb is connected through a 1 Amps bridge rectifier and TRIAC component to the main power supply. Here the gate terminal of TRIAC is connected with optocoupler MOC3041, this optocoupler is driven by the output of timer IC555. This timer IC 555 produces a timing pulse depending on the timing resistor and capacitor (R3, C2) components. Now when we press the push button to the ON switch, the load is connected to the main power supply, and the timer IC gets supplied. So it produces a timing pulse, which will drive the optocoupler in a few seconds. Then the load is disconnected from the supply through TRIAC. Switch S1 should have a current rating corresponding to the load. Multiple switches can be installed in parallel to switch S1 to turn on the bulb from different places. Let’s say from the top and bottom of the stairs. The circuit runs directly from mains power, so take utmost care while assembling.
Applications
Used in a staircase or some other application where we need a few seconds of lighting.
