I picked up an LCR meter for the main purpose of winding transformers and being able to nail down the actual inductance and transformation ratios. The meter was advertised as "Frequency to 15MHz" but
Steve To measure inductance at the frequency of use, I use either of two instruments. I have the Autek VA-1 and the AEA HF-CIA antenna analyzers. This method would work with the MFJ anatenna analyzer
At 05:36 PM 11/13/03, Steve KK7UV wrote: I picked up an LCR meter for the main purpose of winding transformers and being able to nail down the actual inductance and transformation ratios. The meter w
What are you trying to wind Steve? Odds are it has been done before, and someone could help. < It actually generates a 1 kHz signal for measuring inductance which probably makes it worthless for meas
Steve KK7UV wrote: . My question to the group is what do you use to measure the inductance of the windings so you know when you reach the desired ratios? I've had miserable luck doing it by formula a
It's worse than that. If the transformer EVER had DC flowing in its lifetime, it can have permanently reduced permeability, because it has been partially magnetized, like the old magnetic core memory
At 08:11 PM 11/14/03, you wrote: If you damage a core with DC, you can heat it to the Curie temperature to demagnetize it. Rick N6RK You can also essentially demagnetize the core by cycling it around
I wouldn't want people to think this is a big problem with all cores, or even most cores we use. In my experience, this is a non-issue in the soft iron cores we normally use at higher frequencies. I
The very popular Fair-Rite 43 is not immune from magnetization, as I have tested it. I suspect 73 is at least as bad. The issue comes up for me because I use DC in my system to switch relays. If the
This is referred to as a common mode choke. Differential (odd) mode current would not affect the core. Common (even) mode current would be able to affect the core if of sufficient magnitude. In any e
At 11:22 AM 11/17/03, Richard Karlquist wrote: Also, the RF chokes used to feed the DC into the coax cannot be wound on non-gapped ferrite cores, like toroids. I see this all the time in commercial e