General > General Technical Chat
Powering an LED from international line voltage
NiHaoMike:
--- Quote from: kenyonshutt on May 03, 2024, 06:55:36 am ---That's possible, but to keep costs low, I'd like to stick to only one LED. Thanks for the idea though
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Tiny SMD LEDs are dirt cheap. Design a small board with a whole lot of them on one side and some support components like a diode bridge on the other. (The main dropping resistor and/or capacitor remains external.) The tiny bit extra you spend on the LEDs is offset by the savings on the supporting circuit.
--- Quote from: soldar on May 03, 2024, 07:53:02 am ---How about the classic NE-2 indicator lamp?
https://en.wikipedia.org/wiki/Neon_lamp
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My experience with a NE2 and a modern LED in series (for a charge indicator on a high voltage capacitor module) is that the LED appears much brighter for the same current. The efficiency of those small neon bulbs is really low.
soldar:
If all you want is an indication that power is ON then NE-2 neon + resistor is difficult to beat in terms of simplicity and reliability. It is what is still used in switches and power strips. I have quite a few that are half a century old and working like the first day.
mikeselectricstuff:
--- Quote from: soldar on May 03, 2024, 01:41:29 pm ---If all you want is an indication that power is ON then NE-2 neon + resistor is difficult to beat in terms of simplicity and reliability.
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Where do you get the surface-mount NE-2's from ? :D
mikeselectricstuff:
--- Quote from: NiHaoMike on May 03, 2024, 01:15:30 pm ---
--- Quote from: kenyonshutt on May 03, 2024, 06:55:36 am ---That's possible, but to keep costs low, I'd like to stick to only one LED. Thanks for the idea though
--- End quote ---
Tiny SMD LEDs are dirt cheap. Design a small board with a whole lot of them on one side and some support components like a diode bridge on the other. (The main dropping resistor and/or capacitor remains external.) The tiny bit extra you spend on the LEDs is offset by the savings on the supporting circuit.
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There are also LEDs with multiple die in series in one package, mostly white for lighting applications.
soldar:
--- Quote from: mikeselectricstuff on May 03, 2024, 01:52:29 pm ---Where do you get the surface-mount NE-2's from ? :D
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What a great business idea! :)
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