Most circuits do not consume too much power during light off. However the standby circuit still consumes little current.
This circuit uses a relay to cut the power completely after time out, such that no electricity is consumed during standby.
Step 1: The Circuit
1. LED light
- LED in series with one 200ohm resistor
2. timer by 555
- the 1k, 33k resistors and 470uf capacitor will turn pin 3 to ground for around 10 seconds
- when pin 3 is low, transistor will switch on so relay close and circuit is on
- when pin 3 is high, transistor will switch off
- hence relay will open and circuit is off
The flow logic is like this:
- when you press button to turn on the ciruit, LED is on and timer is on
- even when you release the button, as the timer is on, the relay remains close so electricity goes through relay to the LED
- when timer is off, relay losts power so relay is open and the circuit is disconnected from battery
- LED is then off
Step 2: The Material
555, 1k and 33k resistors, 470uf capacitor
- choose different resistors nd capacitor for differnet timer setting
1k resistor, npn transistor (I used 9013), 3v or 5v relay
Step 3: The Deliverable
I don't have a button so I used a wire to touch the positive end of battery to switch on.
The circuit will keep light on for around 10 seconds then you will hear a tak sound from relay and the light will be off.
When off, zero power will be consumed.
That is all. Enjoy !