# Help for voltage is being passed trough load, even triac is OFF condition

We are using below circuit for home automation. We are facing problem when 5v battery is not passing to the circuit,but even 1 volt is being passed trough load, even triac is OFF condition.. Please help us to fix this issue.

• Where exactly are you seeing 1V? What do you expect to see? What kind of bulb are you using? – Elliot Alderson Feb 6 '19 at 17:48
• And what is the supply voltage? And why are you concerned about 1 V? Note that you have a snubber, C1, R2, bypassing your triac so this will pass a small current. – Transistor Feb 6 '19 at 17:54
• For a CFL/LED bulb with a bridge rectified input, the input resistance below 2 diode drops is extremely high. Leakage across the snubber network can easily develop that potential. – sstobbe Feb 6 '19 at 18:38
• Based on the OP's comments to my answer I suspect the OP is using LED lights. They will have a dim glow at 500uA, leaking through C1 and R2. – Sparky256 Feb 7 '19 at 19:56

As long as you are plugged into an AC supply the snubber circuit (C1, R2) to protect the triac from inductive loads is going to allow a trickle of current to flow. Yes, without a load to drag the voltage down the triac output would be a shock hazard.

At 120VAC the leakage is only about 500uA, so at 240VAC it becomes ~1mA, enough to hurt but not burn.

SCR's and Triac's often have snubber circuits to protect them from inductive loads such as motors. There is usually a warning label stating that with AC power plugged in to an active AC outlet there is a potential shock hazard, mostly if there is no load to drag the voltage down. That is a small load to even have 1 volt across it.

NOTE: If you use LED lights they may glow some even if the Triac is OFF. The fix for that is to always have a small load, even if it is hidden, to keep the voltage too low to turn ON LED lamps and too low to ever be a shock hazard.

• Thanks Sparky256, Could you please share us any useful circuit to fix snubber voltage leakage. – venkat y Feb 7 '19 at 13:47
• The 'fix' is to keep a minimum load on it at all times. It is working like it's supposed to. You cannot change the design to make the leakage current go away. – Sparky256 Feb 7 '19 at 14:41
• 1 volt across the load is NOT a shock hazard. – Sparky256 Feb 7 '19 at 14:43
• but we are getting issue with celling dimming with this triac snubber voltage leak – venkat y Feb 7 '19 at 15:07
• Then buy a different type of dimmer. – Sparky256 Feb 7 '19 at 15:23