Quick and Dirty resonance check
We have used a really trick, used for years here from finding resonant
frequencies. No scope or meter required. You need only a good frequency
generator. We prefer the old clunky ten ton vacuum tube Hewlet
Packard units of the 50's and 60's with 50 ohm output impedances.
Buy two real good (expensive) radio shack ultra bright red LEDs. Hook
them in parallel, but reversed anode to cathode. put the pair in
series with the hot line of the generator and hook to the base of the
coil under test. (ground the generator's negative or common lead) I use
a full 5 volt RMS output signal from my generator. Tune the generator
until the leds are at their brightest and then read the dial. (assumes
dial is fairly well calibrated.) This is just tuning until max base
current flows (resonance)
Note! A modern 600 ohm generator can be used with reduced brightness.
A single LED will also work. The key to success is a healthy voltage
output from your generator and ultra efficient LEDs.
Therefore, the first major hunka' test gear for the coiler after a good
meter is a good signal gen. A scope should be way down on the buying
list for a beginner.
Richard Hull, TCBOR