Rap 'n Tap
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From: Gabe Velez
Date: 9/3/99
Time: 9:09:52 AM
Remote Name: 205.219.233.54
Hi,
I had written concerning a couple of things to the admin of this site and have not gotten a response.
I would like to join this society, but if I can't get a reply within a relatively decent time (at least a week. It has been two) period, I would wonder if it was worth it. So far from what I have seen it is, but I would like a better reply time, please.
I hope this doesn't sound too hard, cuz I don't mean to be that way. I would just like to be able to correspond with the group and contribute not just monetarily but with my gems of wisdom (even if it *is* cubic zirconia).
Basically, I wanted 1) to get into the club The Ferrite Core,and can't find it on Yahoo, and 2) get the free sample copy of the newsletter.
Please email me at gvelez@trigon.com.
Thanks a bunch for your listening ear/reading eye and this great site!
Gabe
From: Paul aka ferrite61
Date: 3/18/99
Time: 1:35:22 AM
Remote Name: 206.83.86.126
Well, it goes like this.... if you use the center-tap ground, 1/2 the turns carry the signal, and the other half of the turns are "mutually inducted" to the turns carrying the signal. Mutual inductance has a rule of thumb value of half the effect of using all the turns. In this case the turns would be doubled, and the effect of using all the turns would be to quadruple the impedance. By figuring the mutual inductance rule of thumb, the impedance would only double. In short, the other half of the turns still effect the impedance. Understand that if these remaining turns did not exist, the transformer would be rated at 1/2 the stated center-tap impedance. Here's an example... a transformer is rated as 1000 ohms CT on the primary side, and 8 ohms CT on the secondary side with a signal of 1000 Hz. In order to achieve this both sides of the CT must be grounded. If you don't ground the CT on the Primary side, the impedance will be about 2000 ohms, and the secondary won't change too much ( these things are cheap, don't expect too much from them). If you could unwind the primary side to the center-tap, remove the excess wire, and repeat this, you would get an impedance of about 500 ohms.(obviously, there is no longer a center-tap). Just a rule of thumb, not gospel. I don't have much in the way of testing equipment, just a basic Digital Volt Amp Resistance meter, its not true RMS AC. I need the rules of thumb.