Why different gauges?

[Mr. Apol]

A simple question: in winding the bifilar coil, why are two gauges of wire used? Is it just to differentiate between the two circuits? I ask because I have a prewound bifilar coil of annunciator wire, plastic insulation, in the same gauge (22 gauge), but one strand has red insulation and the other white. Could this be used in an SSG as is?

PBT

[tachyoncatcher]

power efficiency

Hello @Mr. Apol,
You can use the same size wire for both coils. The reason, as I understand it, is for the sake of efficiency. The trigger coil will use less power to trigger the transistor if it is smaller. While it does give back, it is not where the "radiant" comes in from. Therefore smaller wire makes sense when trying to build the most efficient device. Some have just used fewer windings for the trigger while using the same gauge wire. Myself, I did as you're proposing and had to use a higher value resistor on the trigger coil for proper timing. Good luck with your build.
Randy

[Mr. Apol]

Resistor value

Thank you for your reply. What size resistor did you have to use?

PBT