Brainiac75
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Will this really zap me?
🕑 Added 2021-05-21 16:12:00 +0000 UTCIn my April video here in Patreon, I showed you the 400W UV cannon. Odd in many ways, but an alarming oddity is the warning about 'never touch the plug's contact pins!'
Could this light fixture zap me with 230V when unplugged?
Let's dig deeper into the mystery...
Lots of info in this one. You can press 'K' to pause the video, 'J' to rewind 10 seconds or 'left arrow' to rewind 5 seconds :o)
Next public video is planned for release next Friday, May 28th. I will measure a feature of laser beams I haven't tested before.
Comments
Hehe, producenten kan ikke gøre for, at jeg bruger det forkerte stik i væggen uden jord. Med det rigtige vægstik, vil lampen være jordet. Og velkommen til, Henning! Vil du bare krediteres som 'Henning' i mine videoer?
Det er da så fint at jordledningen er monteret i lampen, når der ikke er jord monteret i den anden ende af ledningen.
Hm, I am not sure about the voltage of a capacitor in an AC circuit. This is Big Clive and Dave's territory :) If the half-life of voltage is 1.7 seconds for a 240 V charge I don't think the capacitor has been at full voltage in any of my tests. Some claim that the UV lamp is actually rated as an 130V bulb, but what would control the voltage in this simple circuit? The ballast should not work as a transformer. But usually a capacitor in a 240V circuit would be rated for say 450V - not 240V - to account for the peaks in 240 Vrms AC cycle (around 339V). So much to learn about electronics for me :D
Yeah, it is a little better inside than I imagined. I think the CE marking is legit - though I am in no way an expert on this. I guess the power meter has an AC to DC converter and runs on DC internally. So feeding it with DC is not an issue? And yes, it looks like the person assembling the unit switched mounting holes for the safety rope and capacitor x) I am considering switching them back. The capacitor will be in a slightly cooler place and not have its wires dangling on the ceramic fixture. I will not need the safety rope key bolt, since I am not planning to have this light hanging anywhere.
Bob Drucker
Of course the voltage on the capacitor depends heavily on exactly when you turn it off doesn't it? I mean that it depends on where in the 50 Hz cycle you turn the power off (could be +/- 240V across the capacitor or anywhere in between).
Bob Drucker
If R is 100K and C is 25 uF, that's about 1.7 seconds half-life on the voltage.
TechieSteve
Looks like a proper mains capacitive noise suppression unit. Curious the power meter seems to be able to live for a bit on the back-fed DC. I'd want to take that apart now and have a look at its power supply circuit! I'm still chuckling about the safety line attachment point :-D
