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Old 05-14-2019, 01:51 PM   #21
wvgca
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as a further explanation, when I said INTERNAL I meant 'as part of the assembly' / covered with the shrink tubing, NOT as part of the LED die itself ...
as far as I know, no LEDs are manufactured with the resistor being part of the die , and / or built into the LED itself during the manufacturing process...


sorry for any confusion ...
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Old 05-14-2019, 01:55 PM   #22
gregc
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can you show us a datasheet for an LED that operates at 12V?

An engineer doesn't use ebay postings as a technical reference.
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Old 05-14-2019, 06:47 PM   #23
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Originally Posted by gregc View Post
can you show us a datasheet for an LED that operates at 12V?

An engineer doesn't use ebay postings as a technical reference.
Glenn, get realistic. This is not a NASA design excersize, it is a model RR forum. You can by yourself go to Mouser or Digikey and select LED thru hole. Then after the LEDs come up on the page, select 12 volts shown as 12V. The datasheets will appear next to item.

As for the rest of you reading this, be assured 12 volt white LEDs exist and 100s are available on ebay. If missing the datasheet, be assured the LED will last as long as a LED with a datasheet. 10ma & 20ma are for sale. ma is short for milliampere that is the current the LED uses at the rated voltage.
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Old 05-14-2019, 08:48 PM   #24
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I went to Mouser online, and selected LED, 5mm, standard thruhole, and 12 volt, . Only red, green and yellow...surprisingly only 15 came up ... out of hundreds of thousands of LED in total, warm white or cool white, was NOT an option there ...
Manufacturers were Broadcom, Lumex and VCC ..


they do make them, surprisingly .... but very expensive, single quantity was over a dollar each, while normal led were maybe a cent or so each ... 100 times the money ..

however, the majority of ebay, and others carry the standard leds, which light up just over 3 volt for the white, and are either hooked up in series, or have a resistor included under the shrink wrap ..
so yeah, they make them, but this is really grasping at straws ..


ps .. who is Glenn ?
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Old 05-14-2019, 08:57 PM   #25
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I went to Mouser online, and selected LED, 5mm, standard thruhole, and 12 volt, . Only red, green and yellow...surprisingly only 15 came up ... out of hundreds of thousands of LED in total, warm white or cool white, was NOT an option there ...
Manufacturers were Broadcom, Lumex and VCC ..


they do make them, surprisingly .... but very expensive, single quantity was over a dollar each, while normal led were maybe a cent or so each ... 100 times the money ..

however, the majority of ebay, and others carry the standard leds, which light up just over 3 volt for the white, and are either hooked up in series, or have a resistor included under the shrink wrap ..
so yeah, they make them, but this is really grasping at straws ..


ps .. who is Glenn ?
I went to Mouser and white 12 volt 10ma were 80 cents each. I shop ebay for fifty 12 volt 20ma LEDS for under $10. That is under 20 cents each. My new set up had no issues with ebay LEDs.
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Old 05-14-2019, 09:23 PM   #26
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I went to Mouser and white 12 volt 10ma were 80 cents each.
can you provide a link to the datasheet? or at least a part #?

here's an LED rated at 12V for 80cents LTH3MM12VFR4400. what does datasheet say?
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Old 05-15-2019, 04:49 PM   #27
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can you provide a link to the datasheet? or at least a part #?

here's an LED rated at 12V for 80cents LTH3MM12VFR4400. what does datasheet say?



if it's the same as the 5mm parts [next to no sources, and pricey] they DO come in a 12volt version ... they have 'built in' dropping resistors so that they function on 12 volt, not the standard voltage .. the dropping resistor is INTERNAL to the LED die itself ... built in when they make it ..
sourcing is extremely scarce as you might imagine, lol , and not enough made [or sold] to really matter anyways ..


i really do not recommend these due to price and availability, an external resistor is much easier
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Old 05-16-2019, 01:21 PM   #28
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Personally I like the strips sold on ebay for 12v 'automotive' use. Those have the resistors built in and are usually designed so you can cut them apart between every set of three. Makes it easy to get the length you need and 12v power packs are a dime a dozen.
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Old 05-16-2019, 02:19 PM   #29
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Personally I like the strips sold on ebay for 12v 'automotive' use. Those have the resistors built in and are usually designed so you can cut them apart between every set of three. Makes it easy to get the length you need and 12v power packs are a dime a dozen.

Yes, the three LEDs in series with a dropping resistor work very well on 12 volt ..
and the power packs [normally wallwarts] are easy to find ..
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Old 05-16-2019, 04:01 PM   #30
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There are some FLASHING LED's with built in resistors and flashing circuit in the resin of the LED casing and they will run directly on 12v. I believe they are the only kinds out there.
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