How to Reuse Toroids
I am trying to re use some toroids that I salvaged from a broken computer PSU and motherboard. I have some electronics experience however this is mainly with digital circuits. I am reusing the toroids by removing the original windings and hand winding the several coils required by the circuit. I have noticed that while the one largest (2.2cm diameter) core works exceptionally well, all other cores salvaged from the devices work poorly. My goal is driving a nixie tube. While the "successful" core yields about 180 volts AC the rest can barely top 60v output (all have similar numbers of windings, roughly 150 turns on the primary, 5tap5 on the secondary, 10 on the feedback).
Clearly there is some level of variation between how the toroids perform. Is there any easy way to work out which cores will work? Can anybody explain which factor(s) are likely to be the cause? Visually the cores appear to be the same, looking like they are all made of soft iron.
For reference, I am using the toroids to make a Royer
oscillator - which does appear to be working, as my source voltage is 5V.
Any help appreciated,