I feed one of the 2 windings 12 Volts in here 13.8 V ~
In a wire, I measure 0 Volt
And by making 1 turn around the toroidal transformer, I get 90 mV
I realize this time 2 laps
We obtain the double: 180 mV
3 turns: 270 mV (with the right caliber!)
Rule Voltage (Volt) per revolution: allows to quickly know the voltages