[Boatanchors] Looking for Documentation on IM-5210 HV Probe

[Barry L. Ornitz]

Bob, N0DGN, wrote:


> This one is blue and completely self contained.  The meter is built
into the
> body, along with an on/off switch in the handle.
>
> An obvious Heathkit design and so noted by the model number.  It
works
> wholly in a stand-alone mode.
>
> This is why I am seeking out Heathkit documentation

Look at the meter for any indication of the movement sensitivity.
Typically it will be 50 microamps full scale or 20,000 ohms/volt.  If
the meter is rated to 50 KV, then the series resistor will be 1000
Megohms.  Your unit is nothing more than a simple meter in series with
a special high voltage resistor.  The switch just shorts the meter
movement.

My comments about the cleanliness of the probe and how it was stored
still apply.

I once did considerable research into electrostatic spraying and
routinely worked in the 50 to 100 KV range.  For voltage measurement I
purchased a Julie Research meter.  It looked like something out of a
science fiction movie - six inch diameter aluminum ball on top, with a
three foot long, oil-filled glass pipe from the ball to the grounded
base.  Inside the glass was a string of precision resistors.  The base
had a taut-band meter for readout.  These are considered the
gold-standard when working with high voltage.  I compared my personal
HV probe, the one in my lab, and an RCA meter similar to yours from
our company electronic shop to this meter.  None were closer than 10%
to the Julie and the actual reading varied from day to day depending
mainly on the humidity.

These inexpensive meters and probes were sold to test the high voltage
supplies in televisions where actual accuracy was not too important.
If you wish to measure in the range of less than 5 KV like you might
find in a kilowatt amplifier, look for a 10X probe rather than a 100X
one.  Or better still, buy a good meter and multiplier resistor from
Mendelsons or Fair Radio.

         73,  Dr. Barry L. Ornitz     WA4VZQ     ornitz@tricon.net