Recently, I built the “Noise Inspector” with the objective to help me measuring inductance and transformers. After working with it for a little while I realised that the proposed testing circuit wasn’t correct. The bias current of the inductor under test won’t allow the use of the noise inspector unless the loop back to the variable HT supply is done before the sensing resistor:
Yet, there is a limitation with the above circuit. Unless we add an amplifier between the generator and the test circuit, the DUT will only see a couple of volts (rms) and measured inductance will be lower than the expected. Continue reading “Measuring choke inductance”