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Re: impedance meter - Wavetek 27XT
Original poster: "Luc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ludev-at-videotron.ca>
I have some resistor like the 20 meg you use in your meter, mine
are 220 meg, they are find for 60 cycle but will give you false
reading if used at high frequency because they have to much
inductance. You could built your resistor your self
MultiMiniResistor ;-) in one of these patterns:
I use this pattern too before see:
But I think the zigzag pattern is better.
Tesla list wrote:
> Original poster: "Kevin Ottalini by way of Terry Fritz
> > BUT... Don't take any LIVE measurements with
> > this meter... although full featured, it's very
> > electrically fragile.
> This is very good advice too!
> Early on, I used my DMM with a Fluke HV probe to monitor the
> DC voltage at the tank capacitor, at least until I noticed that the
> display on the DMM kept getting messed up or even weirder
> things would happen.
> Eventually that DMM (an inexpensive Beckman) went weird
> It wasn't the HVDC that was the problem - the probe is designed
> to convert that ... it was the induced noise and voltage and current
> that was affecting the DMM.
> The key here is the Fluke HV probes are high-impedance, high
> resistance dividers. The internal resistor in the probe is
> 1000Megohms and is designed to work with a 10 Megohm DMM
> to give 1000:1 divider ratio, so the DMM is set to volts;
> IE: 40V on the display is = 40,000V at the probe tip.
> As a check, the weirdness happened even when the probe was
> not hooked to the tank cap ... the probe wires made a good antenna.
> > The BEST voltmeter for TC work is a Simpson
> > panel meter mounted in a small box with banana
> > jacks for test leads. Never fails and can be used
> > to monitor voltage drop and other live voltage
> > measurements.
> Indeed! Now I use a simple panel meter and big resistors during
> live TC work. I put together a little web page with schematic and
> info on it:
> Even when monitoring the input AC current, I prefer a
> panel meter or a clamp-on with a movement over a digital.
> > Original poster: "Jeff W. Parisse"jparisse-at-teslacoil-dot-com>