LED comment

[robertglines1]

For those who have had problems with them not burning.. They are +   -  positive negative sensitive.  Also  They are available in DC  or vac in 12 or 24 volts.. I use DC  only as it is compatible with the bus/Rv battery voltage. Just a couple of lessons learned..  I have over 50  lin ft run off 10watt 12 volt DC. (of the strip lighting) So if it don't work ck things out. Pay close attention when making end to end or fixture wiring.     FWIW   Bob 

[TomC]

This is the whole purpose of a diode-it is an electronic device that only allows electricity to flow one way. This is what allows us to use an alternating current generator (commonly called an alternator) for our DC power purposes.

I haven't heard of a either AC or DC diode. I do know when a LED is used with AC, you can see a faint flickering of the LED. That is the LED turning off and on 60 times a second. With DC, they burn continuously. Good luck, TomC

[uncle ned]

I believe that 12 colt ac led lights have a diode in them that lets half of them to burn on each ac cycle.

I ordered some 12 volt ones they came with a 12 transformer. I cut and installed them using the transformer. after if finished I moved them to the coach 12 volt and only half of them worked.  Any one want some cheap.

uncle ned

[Lin]

The "D" in LED stands for diode.  Considering that diodes are like check valves that allow flow only one way, they must be wired in the correct direction.

[shelled]

aaaargh !

yes, LEDs require correctly wired Direct Current (DC).

To use with alternating current,  a multiple LED string/strip can be wired so only half work at a time during the fluctuations of the AC cycle, BUT a better way that uses all the LEDs in the string all the time is to place a diode bridge inbetween the AC power supply and the LEDs.  The diode bridge redirects the current flow so that both parts of the AC cycle look like DC to the LEDs.  Cheap LED strings for use with an AC power supply omit the diode bridge on the assumption the purchaser's decision is based on the number of LEDs only.

As my old Latin teacher said "Caveat emptor" (Buyer beware).

edward

[Van]

Hiya Bob. Thank you for ya help the other day. As it turns out we found these guys  http://smartledlv.com/  last week after I spoke with ya, and they are local to us. We used 4- 16' foot reels to finish off the Airstream Trailer we are doing for a customer.

Warm white, 600 leds per roll, Turned out well. Thx again  

V-man

[DrLed]

The LED strips are indeed sensitive to polarity (plus & minus). Furthermore, the ones built on standard bulb bases, e.g. the common single or double pin bayonets, are designed to the polarity of the base. That means the pin is positive and the shell ground (negative). An incandescent will work either way, so an incorrectly wired socket was not an issue, but it will be for a LED in the same socket. Led with a bi-pin bulb base, e.g. those used in the typical halogen fixture, are also polarized. If they don't work one way, rotate them 180 degrees and they should light up.

However, the better quality LED bulbs designed to replace 12v fluorescents usually have internal circuity to handle either polarity. Those from Revolution and Ming are examples of this.

[Oonrahnjay]

The LED strips are indeed sensitive to polarity (plus & minus). Furthermore, the ones built on standard bulb bases, e.g. the common single or double pin bayonets, are designed to the polarity of the base. That means the pin is positive and the shell ground (negative). An incandescent will work either way, so an incorrectly wired socket was not an issue, but it will be for a LED in the same socket. Led with a bi-pin bulb base, e.g. those used in the typical halogen fixture, are also polarized. If they don't work one way, rotate them 180 degrees and they should light up.  ... 

    I've mentioned a couple of times that I bought little "wafer" type LED's from RVLEDBulbs.com to fit in my puck-light overhead light fixtures.  They are "G4" LED's - I think that that means that there are two little wire prongs spaced 4mm apart; they fit perfectly in the "typical halogen fixture", as noted above.  It took nearly two dozen to change all the overhead lights on my bus (don't forget, I have two ceilings) but every one worked just fine. 
    (Also, as I've mentioned, I bought the "cool white" bulbs - they're perfect for my grey/blue colors in my interior and there is a very intense feel to them which makes it really easy to read when using them.  Many people who have brown/beige/tan upholstery and natural-wood may like the "warm golden white" colored bulbs better.  The difference in current draw is dramatic.)
Bruce H   North Carolina USA

[DrLed]

That's right, Bruce.  G is the type (bi-pin) and the 4 indicates 4 mm spacing.

I get nearly all my LEDs from RVledbulbs.com. They have a "satisfaction guaranteed" policy that assures you will get a quality bulb that meets your needs.