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Using a non-dimming LED bulb on a dimmer

I have a clip on light that I want to use temporarily for light in a room I am redoing. The fixture has a dimmer on it, but I dont want to dim it, just leave it on full brightness.

Can I use a non-dimming LED bulb on this fixture as long as it's left on full brightness, or will the dimmer damage something just because it's there?

I've never used a dimmer on LED bulbs, so I am not sure. If it's a problem, I'll just use an incandescent bulb, since this is only for a few days anyhow, until I get some permanent lights installed in the room.

And just for the heck of knowing, what does happen if someone dims the non-dimming LED bulbs?

Reply to
oldschool
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Probably no way to know. Symptoms vary from no light to flashing to works ok. I had one fixture that seemed to work, but kept blowing the LED every few weeks. Plug one in and try it. I've had some success putting a 4W night light in parallel with the LED. Just put an incandescent in it and get on with the project.

Reply to
mike

If it really stays on 100% full, no problem. If not

- if it's a CR psu, it'll fry rapidly.

- if it's a smpsu it'll either flicker or fry.

NT

Reply to
tabbypurr

Probably not. Two reasons: 'full' is maybe 90%, and there's an abrupt turnon with dimmer switches that is absent with straight AC. That puts (possibly) extra current through a capacitor dropper circuit, which can burn out the LED power parts, after a few minutes, that ordinarily would survive ONE abrupt turn-on.

Second reason: many dimmers expect a resistive load, and may misbehave in connection with the LED, so 'full brightness' might not be possible for the dimmer. Flicker is not an uncommon result; very annoying.

Reply to
whit3rd

It depends on the bulb, but usually these non-dimming bulbs will have a "capacitive dropper" circuit: the input of the bulb has a series capacitor, followed by a bridge rectifier, and the LEDs in the bulb connected in series on the DC output of the rectifier.

The result is that the LED current is determined by the derivative of the current. This works fine on a sinewave, but the output of a dimmer has steep edges so the current peaks will be much higher at that point and the LEDs will burn.

Reply to
Rob

Can you bypass the dimmer? it's perfectly safe to shunt a two terminal dimmer with a piece of insulated wire.

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Reply to
Jasen Betts

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