VTVM probes

[Richard Post]

Why not just put a small slide switch in the probe to short out the
resistor for AC-Ohms?  A small push button will also do.  I prefer to have
the resistor in the probe.  It limits the current in the probe wiring in
case the wrong type of phone plug (smaller insulator) happens to short out.
It won't protect you on AC but most of my measurements are on DC.  A
shorted phone plug and probe wire runs maximum current of a half milliamp
at 500 volts assuming the resistor is in the right place.

As a teenager, my first probe was for a homebrew RF signal tracer using a
hi-fi audio amp I had previously brewed.  Had the slide switch to pull the
signal diode out of the circuit for audio tracing.  Back then, bouillion
cubes came in a long thin round metal cans.  I put a long pointed screw in
the plastic cover and a hole in the other end for the shielded wire to come
out.  Had fun times repairing radios many years ago.

73,

Rich




At 12:16 PM -0500 2/2/01, Fred Holnagel wrote:
>Re: Probes for Heath VTVM.  At the risk of offending the purists among
>us, a person could install a mini-switch on the panel and switch in a 1m
>resistor that way. A low resistance contact would be preferred. ( Sounds
>too simple, what did I overlook?) Fred W7PRV
>
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