As usual, this thread has been very educational, the mere asking of the question has unleashed many answers, from which I have gained in my own knowledge. The most practical question that I would ask is:
Why the h___ would your component engineering group want you to measure the impedance of a ferrite? There can only be two reasons: either they can’t get a graph of impedance from the manufacturer, or they don’t trust it. If either of these are true; then I wouldn’t buy the ferrite in the first place. I hope that this isn’t a “slippery slope” issue for you. Otherwise, your component engineering group may be asking for V-I curves whenever you want to qualify a new resistor :-). All that said, I can appreciate the fact that you may want to perform this measurement just to learn how it’s done. If you do perform the measurement, I would recommend one little detail. I would recommend that you first find a “known good” ferrite complete with a manufacturer’s impedance graph. Compare your measurements to the graph just as a sanity check. Happy holidays Chris Maxwell Design Engineer Nettest Inc. Utica, NY [email protected]
