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.
													
																	Power off time delay relay circuit. 
									
	
		
	
																	Time delay relay can provide a short delay after power is turned on and before switching on the device. 
																	The following circuit was requested by fastshack3. 
																	The time delay for the common emitter will be approximately 3 time constants or 3 r c. 
																	The circuit is based on the rc time delay and zener controlled switch. 
															
													
									
	
		
	
																	Delay timer with relay i am looking to build a circuit that would control an output relay. 
																	The aim of this project is to demonstrate the functioning of a time delay relay. 
																	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. 
																	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.