Error in measurement with Tektronix Probe 1000:1 ??

Question

Hello!I tried to measure a short high Voltage peak with a little olderTektronix Probe, Part No. 010-025 on a Tektronix TDS 460 Memory-Scope.Concretely I wanted to define the ignition voltage of a fluorescenttube. I guess the voltage is about 1-2 kV (1m length of the tube). Imeasured between 7 and 8 kV with the Tektronix Probe (!) and disagreedwith that, because the C_res on the Ballast-Board has a voltagestrength of 1,6 kV and the expected voltage that I got from a gasdischarge graph is about 1 kV/m.I quantified the divider of the probe with 979:1 on 50 Hz sinus AC,linear with different voltages between 100 and 400 V which I could setup on the isolating transformer.Now the question:Can somebody help to affirm this variation?Is there overshoot common because of the short voltage spike?Thanks for all consideration!greetings,Christian

joesmith · Accepted Answer

Hi,ChristianThe tube is a capacator.j.Mar 9, 10:17=A0am,  wrote:

hrhofmann · Answer

Is it possible that the actual voltage was that high for a short instant before the arc actually struck? I am guessing that for a 1 meter long fluorescent tube it would be no more than 2 kV at the most, if the voltage were applied in a slow steadily increasing ramp up of voltage over a period of several seconds. But, if the striking voltage was from a step-up transformer, it might be much higher for a few milliseconds until the arc was fully established.

I am assuming that you used the word "quantified" in the meaning here in the USA as calibrated or checked or verified the accuracy of the probe.

H. R.(Bb) Hofmann

Peter Dettmann · Answer

Well yes there may be a measurement error. But you only refer to a

50Hz test to establish the probe measurement division. It is essential to properly adjust the compensation elements as described in the manual. I found that due to most people not having suitable signal sources, I ended up with the job of calibrating the x1000 probes in my work place. As a minimum look at the waveform on a fast square wave generator. If that looks ok, your measurement is probably acceptable.

Peter Dettmann

Jim Yanik · Answer

"hr(bob) "  wrote in news:66d93545-28fb-the voltage across the tube is going to increase until the arc establishes itself and then the voltage will decrease to operating V.If the probe is a P6015,then the divider should be adjustable.(and may be adjusted far out on response,too.)I don't recognize the older TEK p/n.-- Jim Yanikjyanikat

Error in measurement with Tektronix Probe 1000:1 ??

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