Touch Delay Switch Module DIY Kit Smart Switch For Light Control
The left dotted portion is ordinary illumination circuit,right side is electronic switch part.
VD1-VD4,VS constitute switch main circuit,VT1,VT2 constitutes switch control circuit.
In normal times,VT2 base no body touch current injection in cut off state.
VD1-VD4 rectified output 220V ripple DC voltage connect with VT1 through R3;VS is off and the lamp is off.
When use your hands to touch polarity M,body leakage will devide voltage through R6,R5,R4;
and it will let VT2 connected,charge saved by C1 will let out through VT2.VT1 will close because of no base current,
VD1-VD4 can be cut off rectified output 220V pulse DC current will let VS connected through R2,and lamp HL shall be on.
When humans hands leave polarity M,VT2 will be cut off because of no base current, R3 current will begin to charge for C1.
Then lamp remains to be on;when C1 is charged to a certain value (0.6V),VT1 will likely be connected repeatedly,VS will lose trigger voltage;
when alternating voltage is over zero,will probably be off immediately and the lamp will probably be off.
Changing C1 capacity will alter relay time of closing lamp, and you’ll adjust it in line with its capacity.