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Trevor Wilson Trevor Wilson is offline
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Default Strange transformer problem.

On 10/04/2014 5:28 AM, Michael Black wrote:
On Thu, 10 Apr 2014, Trevor Wilson wrote:

On 9/04/2014 12:24 PM, Pilgrim wrote:
In article ,
Trevor Wilson wrote:

On 9/04/2014 8:41 AM, Jon Elson wrote:


It is also possible that there was enough capacitance between primary
and secondary to give the 40 V reading without an actual short.

**BINGO! That is the only explanation which makes sense.

Everybody today thinks that a digital multimeter is the be all to end
all.

Give me a good old Simpson 260 any day.

CP.


**I have a Simpson 260.

I never use it. It is purely decorative. Same as my AVO 8 and AVO 7
meters.

The only analog meter I had was some Japanese import, used when I got it
and missing the back cover. It lasted no more than six months, my
fault. The usual problem, trying to measure voltage when in the ohms
position. Or too much voltage. Soon the needle was bent, from hitting
the stop too hard too many times, and then later it practically wrapped
itself around the stop.


**That would be the result of buying a crap analogue meter. In their
defence, decent meters are well protected. In the case of AVOs, superbly
protected.


I was lucky, got the use of an HP410B, which actually went back to the
owner at some point, then became mine when he was moving and getting
ridding of the "excess" (I think he had two other 410Bs).

I have a Voltohmyst that I solid stated, and then a few years ago found
another Voltohmyst lying by itself in a box on a busy street with no
other garbage near it. I hadnt' gone along that street in a long time,
yet there it was for me.

And a Radio Shack DMM in 1984, so I've never looked back. Yes, in a few
circumstances an analog meter is more useful, but not by much. And
there are ways of checking to make sure you aren't getting a phantom
reading.


**Of course. The phantom reading thing has always been about ignorance
on the part of the user, not the tool.


Note that a VOM wouldn't put much of a load on the circuit. Weren't the
good ones generally 20,000 ohms per volt? Assuming a 100volt range,
that's 2megs. A fifth of a 10meg input DMM or VTVM. Maybe enough,
maybe not.


**I have a few meters that are rated at 100,000 Ohms/Volt. Most average
meters were/are 20k Ohm/Volt.


--
Trevor Wilson www.rageaudio.com.au