I don't have your experience or background, Ron, but the L-meter is measuring inductance indirectly and ignoring the presence of distributed capacitance. Maybe it isn't as negligible at the frequency of the meter as you think.
But in the end, it doesn't really matter. The real test is how a particular toroid reacts in the circuit it was intended for. If adjusting the turns spacing changes circuit resonance, then...it changes circuit resonance. That's the result we would have been looking for. Hi. Eric KE6US www.ke6us.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ron D'Eau Claire Sent: Monday, August 29, 2005 5:29 PM To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; [email protected] Subject: RE: [Elecraft] OT: Effect of Compression and ExpansionontheInductance of Toroids? Okay, this is interesting so I approached an answer in my usual way. I grabbed a loose toroidal inductor that had nicely spaced turns filling 90% of the circumference of the core and stuck it in my L-meter. 3.1 uH. Scrunched all the turns tightly together. They filled about 20% of the circumference. Inductance now 3.3 uH. The L-meter uses a low frequency signal so capacitance shouldn't make much difference in the reading. So fully spaced to totally scrunched, in this case, yielded a 9% change in inductance. It's nice to work the numbers, but I've always tended toward a direct experiment whenever possible. Back in school, I always knew where my soldering iron was but was forever forgetting where I had put my slide rule. I haven't changed. (For the newer readers, a slide rule is the ancestor of the pocket calculator. For comparison, a slide rule is to a calculator as working CW on 40 meters is to making a cell phone call.) Ron AC7AC _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
