I am not sure if you just want to test the diac and keep if OK or if you want to repair the fence.
If you are repairing the fence diac's are generally reliable.
One end of the diac will connect the the gate of the SCR. The other end connects to the junction of a capacitor and resistor. The other end of the capacitor connects to ground. The other end of the resistor connects to HT. The capacitor charges via the resistor and when the voltage reaches a certain level the diac triggers and dumps the voltage stored in the capacitor into the gate of the SCR (there is usualy a resistor of around 100R in series with the diac to limit I). Turning the SCR on. The diac then resets allowing the capacitor to charge again.
The diac used in a lot of fences is a BR100. The BR100 has a breakover voltage of 36V.
A neon is used in some fences in place of the daic but circuit values would be different.
The weak link is usually the resistor or series of resistors connected between the capacitor and HT. They are usually many 100's of K and tend to go high or open circuit.
Or the capacitor can go low in value.
Frank
If you are repairing the fence diac's are generally reliable.
One end of the diac will connect the the gate of the SCR. The other end connects to the junction of a capacitor and resistor. The other end of the capacitor connects to ground. The other end of the resistor connects to HT. The capacitor charges via the resistor and when the voltage reaches a certain level the diac triggers and dumps the voltage stored in the capacitor into the gate of the SCR (there is usualy a resistor of around 100R in series with the diac to limit I). Turning the SCR on. The diac then resets allowing the capacitor to charge again.
The diac used in a lot of fences is a BR100. The BR100 has a breakover voltage of 36V.
A neon is used in some fences in place of the daic but circuit values would be different.
The weak link is usually the resistor or series of resistors connected between the capacitor and HT. They are usually many 100's of K and tend to go high or open circuit.
Or the capacitor can go low in value.
Frank
