SCHEMA AND DRAWING
BACK TO EL509 PAGE
The schema is similar with the one form the third step. I used two transformers to raise the voltage input for the potential transformer:
Tr1a = step down transformer 220V/24V 400 VA
Tr1b = step down transformer 220V/24V 500 VA
Their secondaries were connected in serie for 48 VAC at 400-500 VA.
This strange setup is used because i have no variac, and so no possibility to vary the power in my circuit.
maibe sometime in the future I will have a MOT in my hands.