Need same color bi-directional LED 3mm

torsdag den 25. oktober 2018 kl. 01.09.19 UTC+2 skrev Jeff Liebermann:

if you can find any:

AC LEDs, with two sets of back-to-back LEDs, are available for high-voltage high-light-level LED assemblies. For low light levels running from AC, people just use a back diode and run the LED half-cycle at 60, etc., rather than 120Hz.

--
 Thanks, 
    - Win

I've seen such LEDs, know nothing about suppliers though. You might have to put up with a bridge rectifier if you want it to light both ways the same colour, or 2 LEDs.

As well as the obvious configurations I suppose there's always the option of 1 LED, 2 resistors & 2 diodes.

: +-----|>|----+-----|

Huh, can you put an led in the middle of a diode bridge, more voltage drop....

George H.

I've seen some at 75V

a lazy man would go over the led with a black paint marker and call it a day. same colour both ways.

--
  When I tried casting out nines I made a hash of it.

Thanks. Sorry for the delayed reply.

All the "AC LED" hints under the above description seem to be

117/220VAC powered and seem to refer to much larger light bulbs and strips.

There's very little room for a diode bridge or a 2nd LED. The only way I could make that happen is to redesign and 3D print a new white plastic LED frame. The plastic is there to provide voltage isolation between the solenoid wires and the relay contacts and frame: I could cram a small SMD bridge along the side of the relay but would require precision soldering under a microscope, and is too much work. Similarly, I tried to replace the 3mm LED with two parallel SMD LED's. It worked, but again required too much work. The typical 20 degree viewing angle was also too small.

Your suggestion of searching for an AC LED found only one available product that is green in both directions and is exactly what I'm looking for: Ebay has some in the UK: $3.50/ea plus shipping from UK is rather expensive. The best I could do is $0.125/ea plus VAT and shipping from UK: However, they only have 18 in stock and do not plan to order more.

So, I decided to take the easy way out and simply order some bi-color

3mm LED's and deal with the inevitable confusion when it arrives. $9/100 pcs.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Maybe, using two dies; I'm only sure that there are lighted power buttons for PCs that are polarity-agnostic, do a nice green glow regardless of the connections being switched..

This looks like an option, but it's unobtainium.

Of course, a bridge rectifier could adapt a variety of lamps, if the budget allows.

Mouser has 3000 of the LTL-10CEJ red at $0.33 @ qty 1. Seems the green is obsolete though.

Rick C.

that's a 5mm led isn't it. Could you jam 2x 3mm leds in there?

NT

Nope. It's T1 or 3mm. The title of the eBay listing proclaims: "100pcs 3mm Water Clear Bi-color Red Green Light Blingking Flash LED Diodes USA" Oops. Looks like I accidentally ordered blinking bi-color LED's. I guess I can use them to make Christmas ornaments.

Hopefully, the replacements will be the correct part. I'm dead tired from helping repair a wood chipper and converting some tree cuttings into mulch.

I tried it. I can do it various ways, none of which were both easy and looked good. I can't remove the white plastic insulator because it provides electrical isolation between the solenoid coil wires and the contacts and frame. I could fabricate a new insulator with a 3D printer or CNC router, but that's more work than I want to put into this exercise. The best results so far were with two SMD LED back to back. However, it was also too much work and was difficult to see at some angles because of the 20 degree viewing angle.

This is one of the boxes where they'll be used: There are 6 identical relays installed in sockets across the top. As delivered, the single green LED (after the polarity is reversed) does a good job of lighting up the entire plastic relay case. I want to preserve that, which means SMD LED's and burying an LED under the armature contact wires, is not going to work.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Thanks. That unobtainable LED in green is exactly what I need. The data sheet is from 2000 which makes the part 18 years old. That might explain the scarcity.

I'm trying to avoid using red. The shop mechanics and machinists are all used to the idea that green lights means good things and red lights mean an alarm, impending doom, or overtime. I'm already inviting disaster by using bi-color LED's which will light up red in some machines and/or under some circumstances. If I can find some of the Lite-On LED's in green, I'll probably just replace the LED's again, and rotate them through the problem machines.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

I wonder what the problem is with a two-color led on an AC feed, The two colors blend into one, which is what the OP asked for???? Its just that green/red turns into yellow.

A customer's box has an LED that shows a very pretty peach color. I think it is actually a combination of orange and blue in one LED.

How about this one?

A bit pricey at $1.57 and you have to buy 15 min.

Rick C.

sounds like there just isn't room for what you want, unless you buy an unobtanium led. Unless you put a green LED behind the relay in the machine.

I'll skip the joke about going over an LED with a green pen.

NT

Putting the LED on the back side of the relay would probably be usable if I had the room. If you look at the photo of the way these are mounted, the side facing the door is the bottom of the solenoid coil, which is facing the bottom of the LED. One might think that it's not very visible in that position, but the LED lights up most of the clear plastic case and is therefore easily visible from most directions. Putting an LED on the opposite side would probably work equally well.

Also, at 24VDC and 5K series resistor, that's only 4.5ma. I could probably lower the resistor value somewhat and improve the brightness.

Also, thank you for NOT suggesting replacing the LED with a 24V incandescent lamp.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

With a 36v lamp that might even work. Not 24v. You won't even need a colour filter. Why don't you just accept there being no LED in there?

NT

Y'er right. The light bulb might also last longer if I run it undervoltage.

As I mumbled in my original posting, no LED would be perfectly acceptable, but I want something better. Summerizing:

1. All the 4PDT 24VDC relays I can buy from stock today include an LED indicator.
2. All these relays have the diode inserted backward from the way the CNC vertical mill Bandit controller socket is wired. However, I can buy reversed polarity relays from Omron, but really don't want to have two relays on the shelf. Datasheet:
3. I can reverse the LED, but there are some sockets on later controllers that are wired using the standard polarity. With a maximum reverse voltage of 5VDC for the green LED, I don't like running with reverse polarity although a shorted LED in series with

5.2Kohms won't do much damage.

1. Since I have to do the work, I want to keep the rewiring to a minimum.
2. The operators and maintenance people are accustomed to green is good, red is bad. Therefore replacing the LED with a bi-color LED will surely inspire midnight phone calls. Very high on my list of design priorities is to prevent the phone from ringing.
3. Various combinations of back to back LED's, SMD LED's, diode bridges, and incandescent lights are not acceptable because they won't fit, require too much wiring, reduce the solenoid to contact insulation,
4. The world market for bi-directional green-green 3mm LEDs seems to have been cornered by evil forces intent on ruining my day.
5. Whatever else I forgot.

Drivel: Why is it that I have few headaches with complexicated problems, while the simple little things, like finding a usable LED, seem to be what is driving me insane?

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

I gave you a link to a usable green/green bicolor LED. What more do you want?

Rick C.

Perhaps free samples? About 100 pcs will suffice.

I replied to your post with:

Since then, I've done some additional digging for Lite-On LTL-10CGJ (green-green) LEDs without much luck: I did find some surplus parts jobbers who claim to have stock, but these tend to have rather high prices. I'm not that desperate for the parts:

Thanks again for the link. At least I now know that the part exists.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558