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Does anyone make high efficiency ac/dc LED indicators

With Google I found a company that has a line of LED indicator assemblies from 6 volts up to 24 volts. As far as I can tell from the power consumption data, they just take two LEDs in parallel and put in the appropriate resistor. At 24 volts, we are talking about 1/2 watt and that can get downright WARM.

BUT, why couldn't "they" put several "tiny" LEDs in series and adjust the resistor so that the same light could be obtained with, say, 5 mA as compared to the more or less standard 20 mA.

OR, for AC use, how reasonable would be it to use a capacitor or coil to drop most of the voltage.

It would be "nice" to have a pilot lamp than can run cool and have a expected lifetime longer than whatever it is monitoring. At 120/240 neon based indicators just don't seem to last very long.

Reply to
John Gilmer
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If you use a capacitor how do you guarantee that there will be nothing other than the line frequency get to the input? Harmonics and impulse noise will not be treaded the same a a clean sine wave at line frequency.

Reply to
Michael A. Terrell

You can't.

That's why:

1) you "back up" the cap with a resistor which will help with the impulses. 2) you "protect" youself with a "60 Hz, _% harmonics label.) >
Reply to
John Gilmer

Poor current regulation, particularly for the lower voltage assemblies. The more LED drop (with a negative Vf vs temperature characteristic) in the circuit, the more sensitive it will be to temp. variations.

It all boils (no pun intended) down to cost. Most buyers are comparing these things to cheapo incandescent or neon units. As long as the lamps last a little longer than the warranty, the manufacturer doesn't care.

Reply to
Paul Hovnanian P.E.

The LED lamps that IDEC sells for their industrial pilot lights have an internal resistor and what looks like multiple elements on a flat surface. They have a bayonet base and are rated 20mA for 6, 12 and 24 volt models, and 10mA for 120 and 240 volt models. I think some of them are brighter than the 1 watt incandescent, but none of them match a 3 watt 120MB lamp.

Mike

Reply to
Mike Lamond

So far there is no LED lamp that can match the effieciency of an ordinary incandescent let alone being as efficient as a HPS lamp. Someday..

Reply to
Spokesman

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