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Re: VOMs
Tesla List wrote:
>
> >From chip-at-poodle.pupman-dot-comTue May 21 21:36:11 1996
> Date: Tue, 21 May 1996 13:24:34 -0600 (MDT)
> From: Chip Atkinson <chip-at-poodle.pupman-dot-com>
> To: Tesla List <tesla-at-poodle.pupman-dot-com>
> Subject: VOMs
>
> Greetings,
>
> I have been thinking of getting a new VOM. Since I don't particularly want
> to smoke it, could anyone make a recommendation? It would also be nice
> to measure capacitance too.
>
> Chip
Chip,
Many more modern DMM's (Digital multimeters) are including capacitance
and inductance ranges nowadays. I find them a bit on the unreliable side
compaired to a dedicated LCR meter (Beckman 875A). A VOM is a classic
analog needled movemnt type meter with far less sensitivity than a DMM.
I assumed you meant you wanted a DMM. The VOM is fast disappearing from
the scene, much to my disgust, because the metered movement allows a bit
of optical integration that the DMM just can't do, period. I have all
three meter types. A VOM from Radio Shack should be about $30.00 a real
cheap DMM might be had from the same source for about the same price or a
bit more. An LCR meter of any real quality will run about $80.00
minimum. I would suggest an old Heath capacitance checker or a Sprague
"teleohmike" capacitance checker. (hamfests for about $10-20) These
older "magic eye" instruments were incredibly robust and more than
accurate enough for the coiler.
Be adived that one single inadvertent check of a cap with a charge
remaining on it will destroy a modern, digital LCR meter. The older tube
units just laugh at such little faux pas on the part of the experimenter.
Richard Hull, TCBOR