The relay time delay and power supply is connected.Specific as follows: for 12 v power supply to the relay, relay not immediately and absorption, relay the output status to: normally open and public disconnect, normally closed and public conduction;Wait for delay 1-10 s (adjustable), relay and absorption, at this point, the relay outputs status to: normally open and public conduction, normally closed and public disconnected;As long as the module power continuously, this state will remain. The delay time is adjustable, (0 ~ 10 seconds) IKncreasing the potentiometer can increase the delay time the capacitor C1 can increase delay time with input power light A relay and indicator lights Controlled ac 220 v / 10 a device.(maximum control equipment 2000 w) Stream with relay protection. The delay time formula: T = 1.1 RC.For example: 100 uf capacitance resistance 100 k T = 1.1 * 100000 * 0.0001 = 11 seconds The on-board equipment on the time delay, prevent excessive current when the car lighter burned on-board equipment. Need to have order to start the occasion, to prevent multiple devices at the same time starting current is too large burning appliances. The main chip: NE555 Working voltage: DC12V Colour:red+green+blue Material:PC, Metal Size: 6.8 x 2.1cm Package Contents: 5 x NE555 Delay Relay Shield Timer Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.