From: Paul
Date: Sun, 07 Jan 2001 22:14:21 +0000
Subject: Re: [TSSP] Top voltage testing
Thanks Terry, You've given me enough info to set up a model of each of these test positions. If I'm allowed to tweak the loss factor and Ctop to match your measured Q and Fres, then we should get a good match with Vtop/Vbase predictions. Did you happen to note the base input current or the V drop across your pad resistor - not essential but useful for autopsy if the gain prediction doesn't match. It'll be interesting to see if we can obtain a reliable match with the third test result, ie the ordinary scope probe. Would be handy if we could. Capacitance to the screen of the probe lead is probably the biggest random factor. With Marc's coils and vsd too, I'm a bit overloaded with jobs for half-a-computer to do, but I'll try and run them tonight. Perhaps, after we've got some working models of these, we could select one configuration and instrument everything for simultaneous readings of Ibase, Vbase, Vtop and Q. BTW, your relatively low Q coil would be ideal for a test of pn2511, equ 9.18 which predicts the frequency difference between that of max Ibase and that of max Vtop. Reducing Q further by insertion of extra inner sonotube should increase the frequency difference. Cheers, -- Paul Nicholson, Manchester, UK. --
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.