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Lamp test setup Here's a more specialized test setup that includes an oscilloscope for the analysis of the time-dependent characteristics of the lamp, a high-voltage cold-cathode fluorescent tube. Keywords: Miscellaneous

Lamp test setup


Here's a more specialized test setup that includes an oscilloscope for the analysis of the time-dependent characteristics of the lamp, a high-voltage cold-cathode fluorescent tube.
Philips_7389_500W_240V_-_NL_1973.jpg Philips_SN21T_250W_BU_-_NL_m1970s_a.jpg test-setup.jpg Set-up_with_reference_lamp.jpg IMG_1077b.jpg
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Filename:test-setup.jpg
Album name:Max / Misc lamps and lighting
Keywords:Miscellaneous
Filesize:509 KiB
Date added:Sep 07, 2024
Dimensions:1200 x 800 pixels
Displayed:18 times
URL:https://trad-lighting.net/gallery/displayimage.php?pid=479
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Comment 1 to 8 of 8
Page: 1

Ria   [Sep 07, 2024 at 12:48 PM]
Nice setup. We must see if we can get our oscilloscope working again, it was playing up last time we used it Confused
Tuopeek   [Sep 08, 2024 at 02:16 PM]
Surely the voltage across the lamp is too high for the scope, at least at pre-strike. Can't work it out from the picture, are your probes capacitively coupled?🤔
Ria   [Sep 08, 2024 at 04:54 PM]
Shouldn't the device being tested should be fed from an isolation transformer..? Wonder
Max   [Sep 08, 2024 at 08:29 PM]
Yes, I took some liberties here but I made sure this was still a safe experiment.

Tueopeek - I used a 100:1 probe suitable for measurements at several kVs. Of course, I attached the probe only after the lamp ignition, and during full regime the voltage is not that high (446 Vrms).
Ria   [Sep 08, 2024 at 08:43 PM]
Someone we follow on Youtube (John Ward) made a voltage divider consisting of 10 x 1㏁ resistors in series so that (on 230/240V) mains you get no more than 24V going into the scope. Might see about making one of those.
Max   [Sep 08, 2024 at 08:48 PM]
Such voltage divider is good enough at mains frequency, but if you want to reproduce complex waveshapes accurately then you have to account for the capacitance as well. There are some design rules that need to be respected if you want to have a probe transfer function which is not strongly dependent on frequency.
Ria   [Sep 08, 2024 at 09:00 PM]
That's true, but we're unlikely to need that. We'll see, anyway.
Max   [Sep 09, 2024 at 09:30 PM]
Depends on your application, but if you want to properly measure the voltage waveform of a mains-driven discharge lamp you will certainly need a proper probe.

Comment 1 to 8 of 8
Page: 1