Re: Including tonal output on a multimeter?

John Doe wrote:

"Paul Hovnanian P.E." <paulh@xxxxxxxxxx> wrote:

Phil Allison Wonderland wrote:

"John Dope"

A long time ago, I made a Tonal Voltmeter for low-voltage
circuits. Pretty simple, mostly just input from the circuit to a
CD4046 connected to an earphone. The idea is to turn small
voltage levels into the corresponding tonal output. Like 0 V
would be a very low tone and 5 V would be a high tone. When I was
doing electronics as a hobby, I enjoyed adding stereo output to
the tonal output, but that's another subject.

I always thought that tonal output could be easily added to a
multimeter. Just occurred to me you guys would know. So that's my
question. It would require a mini 1/8" or whatever jack for the
output, or just use a speaker. I guess you would add a
voltage-to-frequency converter to the output that drives the LCD
display driver or the circuit before that?

** Adding a 1/8 inch connector or similar to a DMM is extremely
dangerous !!!!!!

DMMs must have NO user contactable metal parts that link to their
insides when in use - since the insides can be at VERY
dangerous potentials.

A dedicated, self contained, battery operated device for low
voltage circuit use is the only way to go. Then you can use it on
DC voltages that are not referenced to ground.

Even then, use a plastic case and follow the usual DMM precautions
re battery access, leads coming adrift etc.

...... Phil

Good point.

There aren't workarounds? Optoelectronics?

Possibly. Some Fluke equipment uses opto serial links. But that will
require more complex innards within the meter than an internal speaker.

Fuse?

Fuses don't provide isolation or open for current levels that are
lethal.

--
Paul Hovnanian mailto:Paul@xxxxxxxxxxxxx
------------------------------------------------------------------
Very funny, Scotty. Now beam down my pants!
.

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