Greetings from London. England.
I've accumulated quite a large collection of small surface-mount inductors, many of which have lost whatever markings they might have had in the past.
I know there are some very expensive network analysers and other devices available that are capable of measuring low-value SM inductors but I need a MUCH simpler/cheaper way of doing this, specifically with inductors in the 10nH to 1uH range which are well beyond the scope of most small inductance meters. I don't need accuracy better than about
20% - just an easy means of ranking values from low to high.
The indirect method that I've used for many years when I have needed to measure the value of a (physically larger) wire-ended low-value inductor involves soldering a known-value capacitor across it and then using a GDO (Grid Dip Oscillator - yes they do still exist!) to find the resonant frequency, from which I can then determine the inductance.
This arrangement is impractical for tiny SM components so I'm now considering building up a small range of simple test oscillator units, each with a small clip to hold the inductor under test. The Maxim MAX2605-2609 range of low-cost VCO ICs look ideally suited for this job since they can oscillate over frequencies from 45MHz to 650MHz with inductor values between 1.8uH and 4nH. I could then measure the oscillator's output with a frequency counter and determine the inductor value using a look-up table, or alternatively I could just measure the actual tuning voltage required by the VCO to produce a specific output frequency for a particular value of inductor. Obviously it would be necessary to determine and make allowance for the stray inductance/capacitance introduced by the clip arrangement by testing each oscillator using accurate known values of inductance.
Has anyone in this NG any comments or constructive suggestions to make about this idea? Alternatively, can anyone suggest any suitable low-cost (< $200 or so) devices that can measure small SM inductors?
TIA - Dave.