bigclive
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Cold cathode compact lamp
🕑 Added 2025-08-18 01:12:13 +0000 UTCI was expecting this light to be more complex than the classic hot cathode ones, but it turned out to be simper. Given the higher voltage of the thin cold cathode tubes, I wonder how reliable this design was compared to the more common hot cathode type.
The unsmoothed power supply and diac trigger is very similar to the circuitry of electronic halogen lighting power supplies. I wonder if this unit was intended to be dimmable.
Comments
Big Clive
Diacs tend to trigger around 30V.
Keith W
Are Diacs made to trigger at a precise voltage or are they as accurately made as zener diodes? If they are made to trigger at an accurate voltage, can you put Diacs in series to “tune” the trigger voltage to exactly what you want?
Big Clive
A diac has a voltage threshold, but then suddenly dumps current by dropping to a lower voltage. It's commonly used as a trigger device for triacs in dimmers.
Zeedijk Mike
You have such nice, or is that naughty colleagues. Isn't a Diac basically two Zener diodes back to back?
RonNona
Have you measured the capacity, resistance and voltage of the cock and balls?
