GE LED lights - how are they wired

[olmsb4d2]

Okay I had to run out and buy some LED's at Costco over the weekend. This is the first time I've bought LED's and I've never seen any strings wired like these are and don't understand how these work. I was hoping that I could cut them down to 2 strings of 25 bulbs because I need shorter strings in a couple of places. I've read all the posts about LED lights and how they work so I thought I had it figured out but....

First of all - There are 3 wires coming out of the male plug. Two of these go all the way to the female plug. At the first bulb there is one wire going in the socket and 2 coming out. At the second bulb there are two wires going in and one coming out....and that pattern continues down the string...1 in 2 out, 2 in 1 out. I've never seen anything wired like this

Second - This is a 50 light string. the packaging says the bulbs are 3.3 volts which doesn't make any sense to me because that totals 165 Volts (3.3 X 50)

Third - I don't see any rectifiers that everyone talks about being a part of the string, not exactly sure what I'm looking for but I don't see anything.

I was under the impression that these would be wired similarly to mini lights and I've been cutting those strings to fit my need for a long time.

Any help in understanding these new fangeled gadgets would help.

Thanks

[Dennis Cherry]

That could be correct.

Last years GE lights had voltage doubler circuits in the strings that would allow a 50 and 100 light continuous strings.

However, these are fire hazards to use for animated sequences.

If the lights are going to be static only then you are OK.

[olmsb4d2]

Huh?? A fire hazard if used in animation...that's the first time I heard that...can you elaborate please

[Dennis Cherry]

olmsb4d2 wrote:

Huh?? A fire hazard if used in animation...that's the first time I heard that...can you elaborate please

It was discovered in 2009 by several users who bought these type of lights. The voltage doubler circuit electrolytic capacitors cannot take the Fading and constant ON/OFF we will do in our animated displays.

Some users almost had there houses catch on fire.

[Steven]

I don't think these are the strings with the voltage-doubler. I have some GE strings (that I bought at Lowe's) and they dim just fine. As near as I can tell, this is how they are wired. (Please excuse my drawing; I used the CAD tool called paint.exe.)

The string gets 50 lights on one string by a technique that is patented by GE. (The patent is violated by many Chinese manufacturers.) It runs each set of 2 LEDs in parallel. This adds reliability because if one of the bulbs fails open, the string still lights by sending all the current through the "buddy" LED, which gets brighter, but can still handle double the current. I drew some lines around the bulbs, which shows why there is 1 wire going in, 2 coming out.

Note that this is a full-wave string, but the rectifier is split with one half in each end. This lets the 120V pass all the way to the end while only using 3 wires and still full-wave. Other full-wave techniques either use 4 wires, or pass DC to the female end.


Attached files

[olmsb4d2]

That makes sense and your drawing is perfect in explaining what is physically in front of me. I get it now....all except for the voltage part. 50 bulbs at 3.3 volts per bulb still adds up to 165 volts.

Thanks for taking the time to make the drawing.

[Steven]

olmsb4d2 wrote:

I get it now....all except for the voltage part. 50 bulbs at 3.3 volts per bulb still adds up to 165 volts.

There are 25 pairs of bulbs. Since each pair is wired in parallel, the voltage across the pair is the same as the voltage across one bulb. Thus, it's 25 pairs at 3.3 volts per pair, which adds up to 82.5 volts. The extra voltage is dropped through the resistors at each end.

[olmsb4d2]

I noticed the resistor in your drawing after I sent the reply and thought that might have something to do with it but being new to LED's I had no idea. Do LED strings with 25 bulbs use 3.3 volt bulbs? See I would know that answer if we were talking about mini lights. Do LED's come in different voltages like mini's do?

[Steven]

olmsb4d2 wrote:

Do LED's come in different voltages like mini's do?

Yes and no. White, blue, and green LED's are about 3.3v. Red and yellow are about 2.0v. LED voltages are determined by the physics of the semi-conductor junctions. The different colors are from different materials.

Resistors are usually necessary in LED strings because unlike incandescent bulbs, the voltage drop of an LED does not change much as the current through it changes.

[olmsb4d2]

Thanks...all makes perfect sense now. I appreciate the tutorial.

[Jim Saul]

Steven wrote:

(I used the CAD tool called paint.exe.)

:D:D:D:D:D:D
Thanks Steven I needed a good laugh!
and GREAT job explaining how they work too.