Triac not triggering

Started by Julian104 1 year ago1 replylatest reply 1 year ago39 views

I am trying to reproduce an electric fence unit that was discarded by a neighbour. It was left open in all weathers and very muddy. I've cleaned it enough to identify components and draw the very amateurish circuit diagram below.I have built the circuit onto pro board. The problem seems to be that the triac is not triggering output pulses. The 230v LED is supposed to flash with each pulse. The original transformer was wound onto a UFY ferrite nucleus core, but that is smashed and the windings damaged beyond repair. The original output was 10 Kvolts. I have substituted the original transformer with fairly hefty TV LOPT Flyback Transformer.

I would be very grateful for any advice as to why the fence unit is not pulsing/firing.
Many thanks.

fence project_90176.jpg

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Reply by Bob11April 25, 2021

You haven't given us much to go on. There's no guarantee the circuit you built looks like the circuit you drew. No reflection on you--a number of mine don't either. Wiring errors, failed components, cold solder joints, the list goes on. It would be helpful to have at least voltage measurements at various nodes. Scope traces at key points would be ideal. A brief paragraph on how you believe the circuit should operate would also help, so the rest of us don't have to dig through datasheets to find the trigger voltage of T1, the Vbr of the diodes, etc.