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Re: Resonant measure



Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Mddeming-at-aol-dot-com>

In a message dated 1/22/01 1:43:11 PM Eastern Standard Time, tesla-at-pupman-dot-com 
writes: 



>
> Original poster: "TruckDrivingMan by way of Terry Fritz <twftesla-at-uswest-dot-net 
> >" <Tom.Ansorg-at-t-online.de> 
>
> Hi coilers 
> How must I connect the frequency generator, the oscilloscope and my 
> secondary to 
> measure the resonant frequency? 
>
> Tom



Hi Tom, 

My quick & dirty poor-man's system is to disconnect the secondary from the RF 
ground, tie the ground lead of my signal generator to the RF ground, connect 
a pair of LEDs back to back between the other lead and the base of my coil. I 
then find the minimum frequency at which the both lights peak. This is 1/4 
wave freq. It will reach lower max brights again a 3/4, 5/4 etc.  This can 
usually be read within 2%. Substituting a small resistor for the LED's with 
your scope across it can accomplish pretty much the same thing. On rare 
visits from my MW Tech son, he brings over his $20K service monitor and reads 
the peak to 5-digit accuracy, but I've never been out by more than 2.1%. 
Since my signal generator and I are both of W.W.II vintage, I think it speaks 
well for the method. 
        I really am planning to get SOME updated equipment soon (many of my 
meters are in beautiful dove-tailed oak cases) as many of the experiments 
mentioned on the list seem to require more sophisticated tools. (Suggestions 
Anyone/) 

Ye Olde Bolt Thrower, 
Matt D.