Description Timing from Microseconds to HOURSSimple CircuitryPrecision Pulse Generation Timing FMAX 500 KHzUse a single 4 to 16 VDC supplyExcellent temperature stability 0 005 CAdjustable Duty CycleCountless Application and Information SourcesChip NE555 Characteristic When unconnected with the supply power the state of the module is NO normal open CB and COM are conductive CK and COM are unconductive When connected with the supply power delay for 0 10s the module will in the state of NC normal closed CB and COM are unconductive CK and COM is conductiveSpecification Module Properties NE555 chipDimension 77 L x 23 W x 18 H mm with potentiometer Input voltage DC12VAdjustable time 0 to 10secControl voltage AC 0 250V max 10A DC 0 30V max 10AMax loading 2200WConnection drawing We suggest you using a diode connectiong to the VCC in series In order to prevent from damaging chip of Power Reverse or Voltage Fluctuation The board does not add diode because the power would not enough to pull in the relay for the buck from diode when power is too low Package included 5 x Delay Timer Switch