On Mar 9, 10:59*am, joesmith wrote:
Hi,Christian
The tube is a capacator.
j.

Mar 9, 10:17*am, wrote:



Hello!
I tried to measure a short high Voltage peak with a little older
Tektronix Probe, Part No. 010-025 on a Tektronix TDS 460 Memory-Scope.
Concretely I wanted to define the ignition voltage of a fluorescent
tube. I guess the voltage is about 1-2 kV (1m length of the tube). I
measured between 7 and 8 kV with the Tektronix Probe (!) and disagreed
with that, because the C_res on the Ballast-Board has a voltage
strength of 1,6 kV and the expected voltage that I got from a gas
discharge 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 set
up 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- Hide quoted text -

- Show quoted text -

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