RE: Cheap DMM's

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-compaq-dot-com>

In my experience, any DMM is useless when hooked up in any way to an
operating Tesla Coil.  The voltage spikes just send the display into
never-never land.  It makes no sense to select a DMM for such a "live"
application, because all of them will go berserk, if not sustain damage.

However, DMM's are extremely useful for measuring things when there are no
sparks.  NST short-circuit secondary current and turns ratio (mains hooked
up to secondary, operated in reverse) can be done with any cheap DMM.  But
even more useful is if you spend just a bit more and get one that can also
measure capacitance, inductance, and frequency.  The Wavetek 27-XT is such
a meter and goes for about $!00.  I own one and highly recommend it.

Gary Lau
MA, USA

 -----Original Message-----
From: 	Tesla list [mailto:tesla-at-pupman-dot-com] 
Sent:	Monday, April 08, 2002 8:20 PM
To:	tesla-at-pupman-dot-com
Subject:	Cheap DMM's

Original poster: "Mike by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<mje-at-intergrafix-dot-net>

    I'm certain that this has been discussed before, however my attempt at
finding it in the list archive proved unfruitful.  I'm looking for a very
cheap DMM that I can use in Tesla service without a large loss in money if a
mistake happens and it gets struck by a HV spike.  Although I take a lot of
precautions accidents inevitably happen and its much easier to replace a
20-40$ DMM than a 150-200$ DMM.

    I was hoping to get at least 0-600v AC and DC measurement, 10A AC and DC
current, diode and logic test and 2MOhm resistance.  I've found some that
seem like ok deals.

http://www.harborfreight-dot-com/cpi/ctaf/Displayitem.taf?itemnumber=35017
Auto Ranging, 1KVDC, 750VAC, 10A AC/DC, 32.6MOhm, 200KHz, 32 uF

http://www.harborfreight-dot-com/cpi/ctaf/Displayitem.taf?itemnumber=35021
1KVDC, 750VAC, 20A AC/DC, 200MOhm, 20KHz, 20uf

Any help or constructive criticism is welcome.

Thanks,
--Mike Everett