From: Paul
Date: Thu, 15 Feb 2001 18:53:33 +0000
Subject: Re: [TSSP] top voltage initial meas.
Metlicka Marc wrote: > i have made some preliminary tests on coil #2 using my > techtronics 466 scope and a fluke 873 meter. OK, I've just got time for a quick reply as I have to play out on the hills for a few hours tonight... > the signal generator is padded with both a 100 ohm and 600 ohm resistor > for comparisons as the generator has a 600 ohm output. i saw no > difference in results? That's OK. This test shouldn't be affected too much by base resistance up to around 200 ohms. Things might go a bit wrong with as high as 600. > i used two 10x 10meg 11.2pf probes. ok. > base voltage is 1.87v that's in the right ballpark... > fres is 190.3 khz repeatable Thats about right. > base I is .2043 ua micro amp taken after the resistor (this surprised > me) This sounds to be way too low, I'd expect something around 1 or 2 mA. > base v was 1 Div. 5vdiv. > topv was 4div@50vdiv. > topv 74.8 v Vtop is in the right ballpark, > i switched ab with a 1.2% deviation to the lesser topv Encouraging. > these are some initial coil #2 measurements and were repeated many > times to be sure of the repeatability. Looking promising, and repeatability is good news. You just need to reconsider how you're measuring the base current, the fraction of a uA is way too low. If you're in doubt send us a diagram of how you've connected it all together. Hard to type while putting boots on, Cheers, -- Paul Nicholson, Manchester, UK. --
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.