hi...
i want to prepare a kit for 1 phase half wave rectifier. I want to use ujt for firing of scr. can u plz suggest which pulse x'mer, resister i have to use for scr TY6004?

 

Pulse transformers are 1:1, so just about any will do. The pulse transformer will have specs. From the datasheet on the TY6004, determine the magnitude of voltage that satisfies the gate voltage. Use a resistor that limits current to the value given. And, of course, arrange the pulse out of the UJT so it produces the correct voltage into the pulse transformer.