The circuit diagram below show us a typical circuit for welding equipment. Accurate control of the maximum turn-on delay can be reached using potentiometer P2. C1 can be discharged using DB1 diode bridge and R6-R7 resistors at each line zero voltage. This will maintain the same turn-on delay and resets the voltage charge at each new half line cycle.
Power dissipation can be reduced by the transil through both potentiometers.
