I am currently trying to work out whether a particular PCB is faulty. The board consists of a low capacitance a.c filter in parallel across the line and neutral. The circuit also consists of potentiometer and transistor and few other smaller components which im not sure what they are for. The function of the board is to increase and decrease the power for a motor (A.C). The power goes into the PCB then out and down to spade connectors which connect to the motor.
I measure roughly 50 Mega ohms of resistance across the PCB which is why firstly i assumed it may be faulty, but then when I measured voltage at the spade connectors by the motor I was getting 240 volts. Surely with 50 mega ohms I would have a large voltage drop and not read the full 240v.
So if the PCB is fine and functioning correctly is it perhaps due to the transistor acting as a switch which is why i'm reading such a high resistance while it is not energised.
Thanks if anyone can share any light on the situation.