Ron Lowe wrote:


"Bob Eager" wrote in message
...

Use a voltmeter. You had one, so use it!



Whist I agree with everything you say, modern voltmeters can be
misleading too.

Modern DVMs have such a high input impedance that they can find stray
voltage on longish runs of cable which is actually of such high source
impedance that it will drop to zero volts as soon as any ( even megohm )
load is put on it.

So they can indicate a voltage as present when it's not really.
( Safer than the reverse, of course! )

I trust my old 20Kohm/v AVO-8 for this kind of thing more than my fancy
all-singing Fluke DVM.

I had this problem when measuring the flap/slat asymmetry detection
voltage on an aircraft I used to work on (it was an AC voltage wave
form. 400 Hertz) The modern volt meters used to measure the residual
voltages in the wiring. Reverting back to the milliamp hungry meters
cured this and I could get a proper reading

Never believe a reading from a modern meter, unless you know what you
are doing.

Dave