Timer relay drok time delay relay dc 5v 12v 24v delay controller board delay off cycle timer 0 01s 9999mins trigger delay switching relay module with lcd display support micro usb 5v power supply 4 6 out of 5 stars 132.
Power off time delay relay circuit.
The time delay for the common emitter will be approximately 3 time constants or 3 r c.
The working is very simple and is explained below.
Very handy and simple circuit if your looking to have lights accessories or other devices power off after a preset time has elapsed after power is no longe.
The circuit is based on the rc time delay and zener controlled switch.
Time delay relay can provide a short delay after power is turned on and before switching on the device.
For example a 120 ohm relay coil will draw 100 ma at 12 volts and assumming a transistor gain of 30 the base current will be 100 30 3 ma.
The following circuit was requested by fastshack3.
This would be done in 12v and the sequence will be initiated by a manual switch.