Jump to content

Little confused about LEDs and LOR


Guest guest
 Share

Recommended Posts

Ok so I read yes you can use LEDs if they do NOT have a transformer on them. Is this correct? And if so what do you gues mean by transformer? Maybe someone can just do a quick over view of the "DO'S" and "DON'TS" between LOR AND LEDS. TIA!

Link to comment
Share on other sites

Don't know if this will answer your question or not. I have HD and Phillips LEDs. The HD ones have a "lump" near the plug which I assume is a transformer, the Phillips from last year do not. Both brands get along very well with LOR. There are minis on the same channels as the LEDs. I remember last year it was recomended to add some kind of "power draw" which made triggering the LEDs more effective. The new firmware, I believe, fixed the LED problem.

Link to comment
Share on other sites

Becky_Racioppo wrote:

Don't know if this will answer your question or not. I have HD and Phillips LEDs. The HD ones have a "lump" near the plug which I assume is a transformer, the Phillips from last year do not. Both brands get along very well with LOR. There are minis on the same channels as the LEDs. I remember last year it was recomended to add some kind of "power draw" which made triggering the LEDs more effective. The new firmware, I believe, fixed the LED problem.


A typical transformer around the house steps down 120 V AC to a much lower, usually DC, voltage. These are the fist sized, heavy black boxes that you plug in and take up three outlets on a power strip. These do not work well for powering on and off quickly. I think I heard that each time you turn them off, they have to absorb the current. That's ok if you only turn them on and off every so often, but a typical LOR display would kill them pretty fast.

My guess is that lump on the LEDs is actually a full wave rectifier that basically converts the AC voltage to a DC voltage, but does not step down the voltage. This is used to get rid of the 60 Hz flicker LEDs have and it makes them brighter. LEDs running directly of AC power will only light up half the time, but your eye blurs the light. I am fairly certain that these work fine for LOR, but I don't have any of my own, so I don't know.
Link to comment
Share on other sites

OK, there is not a problem actually running LEDs that have a transformer, like Rocky said, the transformer looks like the big "wall warts" that come with lots of Low voltage electronics. It may or may not in line. The one thing that is the problem with the transformers is they are an Inductive load, and LOR is designed to run resistive Loads. Some people have noted that Inductive loads seem to "Stick On". The solution is to put a small resistive load in parallel with the transformer. This also helps the inrush current when turning them on and off. The only downside to the transformer is you can't really dim them.

Also, this is just a nomenclature thing, but your eyes don't really blur the light... The word implies out of focus. What actually happens is your eyes cannot see things that happen more than about 30 times a second, some eyes can do better some eyes do worse, and this is the basis for video being 30 frames a second. The flicker that can be seen with LEDs is due to the fact that the LEDs only turn on and off 30 times a second, and half the time they are off due to the AC sine wave. With some inactive diodes acting as a full wave rectifier this is reduced because the LEDs will turn on the full 60 times a second, but because of the full wave rectified sine wave they still may have a slight flicker visible by some eyes, Mine in particular. One way this could be fixed is to put a capacitor in parallel with the LEDs after the rectifier; this would keep the charge up and flowing therefore keeping the light on and getting rid of the flicker effect.

This is called "Persistence of Vision" This same effect can be used for spinning LED displays like the clocks or spinning message signs you can get at carnivals.

Link to comment
Share on other sites

  • 11 months later...

Becky_Racioppo wrote:

Don't know if this will answer your question or not. I have HD and Phillips LEDs. The HD ones have a "lump" near the plug which I assume is a transformer, the Phillips from last year do not. Both brands get along very well with LOR. There are minis on the same channels as the LEDs. I remember last year it was recomended to add some kind of "power draw" which made triggering the LEDs more effective. The new firmware, I believe, fixed the LED problem.


The lump you are referring to in the Phillips LEDS is where they put their current limiting resistors. LEDs need current limiting to prevent burnout. Some of the better designs will have a "full wave rectifier" (4 diodes) in the "lump" so the LEDs will get 60 cycles per second of on/off instead of the 30 Hz that cheaper strings use.

While I am on the subject, the difference is that an LED with full wave rectification in the circuitry will almost totally eliminate the noticeable peripheral vision flicker you might see in the corner of your eye when you look away from the string (your eyes are more sensitive to movement and intensity changes in the peripheral vision).

Thus, for my internal Christmas tree lights, I only buy the better strings. It is often almost impossible to determine in advance of the purchase as to whether the LEDs have this feature or not. You usually don't see that information on the box. People won't know what it means.

LED lights don't have internal transformers, so I don't think that is what people are talking about here.
Link to comment
Share on other sites

  • 3 weeks later...

Update: I put the 4-foot LED tree in the link I posted earlier on a LOR channel. The transformer in question is a 24-volt 450mA wall wart that says "For Outdoor Use", but also says on the other side: "Not for use in wet locations."

After being controlled for a week or so, the tree went dead. The transformer primary winding is now open. I haven't yet cracked open the waterproof case to find the cause.

I believe the circuit was never dimmed, but I still need to check all my sequences to make sure. It's possible that putting a transformer on an LOR channel is a bad idea. I may need to use an X-10 circuit for this tree. If I had more of these trees, I would probably use the technique I saw in another thread where channels 1-8 are hooked up to 24VAC instead of the mains voltage.

--
Steve

Link to comment
Share on other sites

FYI- The bottom line on LED's...not to step on anyones toes here.
LED's are a DC device, they require DC voltage to operate, either half or full wave
rectification is required to get the DC voltage.

Hope this helps.

Link to comment
Share on other sites

I have about 10,000 LED's in my show. The LED's from Paul at Creative Display's work great!! I have LED's from Target, Lowe's and Home Depot and you can defiantly tell which ones are from Paul.
HD's, Lowe's and Target (Philips) don't fade very well. they dim, then flicker, then shut-off. I have them alone, and parallel with mini's so there is a load on that channel. Some of them have the "flicker" that you get from half-wave when they are, not just flash.

Paul's fade great. Even on a long fade (6-7 seconds). The bulb color is consistent throughout the whole string, and they don't "flicker" when on.
I have them parallel with mini's and I have them by themselves.
My mega tree is 3200 LEDs from Paul. 32 channels, 16 blue, 16 red and 2 strings per channel. That's not much of a load on LOR and I have had no problems.

Scott

Link to comment
Share on other sites

Shubb wrote:

I have about 10,000 LED's in my show. The LED's from Paul at Creative Display's work great!! I have LED's from Target, Lowe's and Home Depot and you can defiantly tell which ones are from Paul.
HD's, Lowe's and Target (Philips) don't fade very well. they dim, then flicker, then shut-off. I have them alone, and parallel with mini's so there is a load on that channel. Some of them have the "flicker" that you get from half-wave when they are, not just flash.

Paul's fade great. Even on a long fade (6-7 seconds). The bulb color is consistent throughout the whole string, and they don't "flicker" when on.
I have them parallel with mini's and I have them by themselves.
My mega tree is 3200 LEDs from Paul. 32 channels, 16 blue, 16 red and 2 strings per channel. That's not much of a load on LOR and I have had no problems.

Scott


Sounds like he has some good LEDs. I'll want to check them our sometime. Also sounds like they are full-wave rectified.

By the way, Home Depot sells lots of different types of LEDS. I bought some this year for my mega tree and tehy worked great. No flicker, and fades are great. I did not have to use and terminators on them. So I think it depends on why you buy.
Link to comment
Share on other sites

I use exclusively LED strings from Paul. This year when I set up. I have all the roof lights. 2 circuits 1 for border and one for icicles. I have 17 strings end to end on each of these circuits. It was at 15 strings that they no longer dimmed and I had to add a single C-9 resistive load to get them to dim properly.

I know! I know! I broke the rule of 3. Even at 17 strings I am still less than 1 amps. About where I would be with 3 strings of regular 100 minis.



Chuck

Link to comment
Share on other sites

You might also want to check out www.ledholidaylighting.com - I checked out Paul's stuff, but ultimately went with the Diogen product just because of the more positive reviews. Great customer service, and at least with the commercial grade strings you can hook like 130 strings together without batting an eye. Fades are seamless (30 second fades or 5 second fades, act just like you'd want them to). No need to add extra strings or anything like that to make them work. I went with C7 and G12 strings and just awesome match for LOR.

Link to comment
Share on other sites

medman2000 wrote:

You might also want to check out http://www.ledholidaylighting.com - I checked out Paul's stuff, but ultimately went with the Diogen product just because of the more positive reviews. Great customer service, and at least with the commercial grade strings you can hook like 130 strings together without batting an eye. Fades are seamless (30 second fades or 5 second fades, act just like you'd want them to). No need to add extra strings or anything like that to make them work. I went with C7 and G12 strings and just awesome match for LOR.


I checked out that site last year, and unless I'm reading it wrong.. the commercial grade lights are $9 for 25 light set. Creative Display's are (about) $8.50 for 50 light set. It say's plug 125 sets of 25 with a plug adapter that's 3125 lights together.
CD's can plug 50 sets of 50 that's 2500 lights together out of the box.
Figure in the PC discount of 10% and Paul's that seem to be a pretty good price.
I haven't seen ledholidaylighting lights so I don't know if they are same/better quality. But I have had great success with all the lights from CD.

Scott
Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
 Share

×
×
  • Create New...