Hello all,

I have an old Clockwork Timer with 1 NO contact. I wish to use this for a timed operation of Lights/Fans/Waterpump.

Can I use a Triac as a Switch for AC by shorting its Gate to Anode 1 as shown? ( the Snubber is not shown). Or are there better ways to do this?

My constraint is that there is just 1 NO contact from the clockwork timer and would prefer not to use anything that calls for a power supply.



Thank you

 

This will work but it would be better to include a 180Ω resistor in series with the switch.

BUT:
1. The switch contacts on the timer will be switching mains voltage - are they rated for that?
2. The switch contacts will be live and so present a shock hazard if they can be touched. If either of them is connected to a metal frame or case of the timer then that frame or case will also present a shock hazard.

 

I think you have to limit Vgate and Igate, they have maximum ratings you
cannot exceed.

Regards, Dana.

 

Hello all,

I have an old Clockwork Timer with 1 NO contact. I wish to use this for a timed operation of Lights/Fans/Waterpump.

Can I use a Triac as a Switch for AC by shorting its Gate to Anode 1 as shown? ( the Snubber is not shown). Or are there better ways to do this?

My constraint is that there is just 1 NO contact from the clockwork timer and would prefer not to use anything that calls for a power supply.

View attachment 153683

Thank you

Use a 1k resistor between the Gate and MT2 terminals to trigger the triac.

 

Thank you all.

This will work but it would be better to include a 180Ω resistor in series with the switch.

BUT:
1. The switch contacts on the timer will be switching mains voltage - are they rated for that?
2. The switch contacts will be live and so present a shock hazard if they can be touched. If either of them is connected to a metal frame or case of the timer then that frame or case will also present a shock hazard.

Yes, the unit is from an old spin drier and was for 220 Volt operation.

Use a 1k resistor between the Gate and MT2 terminals to trigger the triac.

Thank you. You preempted my second question !!!

I decide on this.