OK, so what's the bottom line? Is the Radio Shack ESD mat any good or should I spring for a 'quality' mat, and if it's the latter, how do I know which mat(s) meet specs?
Nelson, KU0A -----Original Message----- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Alan Bloom Sent: Friday, December 19, 2008 10:49 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] ESD mat measurements On Fri, 2008-12-19 at 08:18, Rich Lentz (KE0X) wrote: > You may get better - different - results if you use an oscilloscope to > measure this voltage peak. The Simpson has ?dampening? qualities and > will NOT show the true peak voltage/current. It shouldn't matter. I was not trying to measure the voltage, rather the RATIO of the voltage before and after the capacitor discharge. As long as the dynamic response of the meter is independent of voltage level, the measurement should be accurate. > Also, have you taken into account any internal resistance of the > Simpson? As I recall that was a 20,000 ohms per volt (a 50 uA > movement) meter - Great at the time, but worthless today for anything > other than house/auto wiring - which also implies that there is a > shunt dropping the meter movement down from 50 to 60 (???? which model > has a range of 60??? I have seen ones with 50 and 100 uA but not 60) > and thus there is resistance added to your "test" circuit. These small > errors are acting like a furculum and greatly skewing your results. As I said, I don't think it matters. Besides, even if the measurement were off by a factor of two it wouldn't affect the qualitative result. The measured resistance was several orders of magnitude too high. > Rich, > > KE0X Al N1AL _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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 No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database: 270.9.19/1857 - Release Date: 12/19/2008 10:09 AM _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
