LEDs and Resistors - Proper resistance for LED lighting Share  Email this topic  LinkBack Topic URL  Retweet this Topic  Share Topic on Google+  Like this Topic  Share on Facebook  Digg this Topic  Reddit this Topic  Share on Tumblr Options  Watch this topic  Print this topic View » Normal Threaded

Previous Topic Next Topic

JDennis		#1 Posted : 01 December 2017 00:05:14(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		I tried to search this but didn't find the answer I was seeking. The ESU instructions are very good and specific as to the requirement for a 470 ohm resistor when connecting LEDs with their decoders. In general I have found Marklin's documentation a bit more -- uh -- challenging. Would I be correct in my conclusion that a) a resistor is required when connecting LED lights to ANY decoder (including Marklin decoders); and b) that 470 ohms is the appropriate resistance value? Thanks.
User Profile View All Posts by User View Thanks

	Wish to join the discussion?! Login to your marklin-users.net community | Forum accountor Register a new forum account. Or Connect via Facebook

PMPeter		#2 Posted : 01 December 2017 00:47:40(UTC) Retweet
Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC		There are various types of LEDs used for model railroading so there is no standard answer except these LEDs are usually operating in the 3-4 volt range and require a resistor to drop the typical model railroad voltage down to this 3-4 volt level. The value of the resistor depends on the voltage requirement of the LED and its current draw. Then it is a matter of Ohm's law to determine the resistor value (R = V/I). Having said that there are model railroad LED lamps available with built in resistors and these are generally direct replacements for older style loco bulbs, built in switch lantern bulbs, older signal bulbs, etc. They do not require an additional resistor. There are LED lighting strips operating at around 12 volts DC that again have built in resistors and do not need additional resistors if you have a 12 volt supply, but require an external resistor if your supply voltage is greater than 12 volts. So depending on the LED type you have, 470 ohm may be sufficient, but it is always worth the calculation if you know the LED characteristics. Otherwise do a test circuit on one LED, measure the voltage across the LED and if possible the current through the circuit. That is helpful in determining the resistor wattage. I have burnt my fingers a few times on a too low a wattage resistor, but fortunately have not created a fire. Probably a more complicated answer than you expected, but there is no one size fits all solution when it comes to MRR LEDs. Peter
1 user liked this useful post by PMPeter		gwolski
User Profile View All Posts by User View Thanks

gwolski		#3 Posted : 01 December 2017 00:51:35(UTC) Retweet
Joined: 17/12/2001(UTC) Posts: 171 Location: Central Virginia		Try using one of the online calculators with the values for your LED and power supply. For example: https://www.digikey.com/...ator-led-series-resistor In this case, I plugged in 12V power supply, 2.2V forward voltage (from LED specs), and 20mA current draw (LED specs). The calculator returned around 490 ohms IIRC. If you change the voltage drop to 6.6v (3 of the above mentioned LEDs in series), you get a resistor value of 270 ohms. Again, take a few minutes to learn Ohm's law as mentioned - it will save you a lot of time! 1. Learn Ohm's law - keep a 3x5 card handy if it's not already burned into your brain 2. Know your component specs - they are definitely not all the same! (I store a card with the values with the parts - i like to use a Plano compartmented tackle box like their 3701 box). No digging or guessing (or burned out LEDs for that matter). 3. Draw out your circuit - what's the power supply? how many LEDs? 4. Use an online calculator to get your resistor value Cheers!
		Gene Wolski
2 users liked this useful post by gwolski		ktsolias, MikeR
User Profile View All Posts by User View Thanks

JDennis		#4 Posted : 01 December 2017 01:20:36(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		Thanks to all. ESU's documentation actually says to use a resistor of 470 ohms to (I think) like 1k ohms. (I'm just replacing the incandescent bulbs with LEDs during the process of converting a loco to digital, one bulb per circuit. None of that tricky addition of resistances.) I guess I was assuming they're talking about the "stock" Marklin replacement LEDs and that these would all pretty much have the same basic specs, voltage requirements, etc., so I guess it never occurred to me that there may be a wide variety of LEDs folks might select and use for this purpose. Silly me. I thought there might actually be some standards at work here. When I bought these Marklin LEDs, they didn't come with any documentation at all, so hard to identify the specs. I'll just do a little testing to see what works. Quote: Again, take a few minutes to learn Ohm's law as mentioned - it will save you a lot of time! While I freely admit to being a complete neophyte in this subject of digital Marklin, and I'm sure that makes me seem like a bit of a moron and that I've never heard of Ohm's Law. Suffice it to say that your assumptions may be a bit off target on both points, 'kay? Thanks. Edited by user 01 December 2017 04:51:23(UTC)  | Reason: Not specified
User Profile View All Posts by User View Thanks

gwolski		#5 Posted : 01 December 2017 01:58:29(UTC) Retweet
Joined: 17/12/2001(UTC) Posts: 171 Location: Central Virginia		Apologies if that came out wrong - not trying to talk down to you. Just trying to provide a framework answer / reference. How's this? White LED's (if that's what you are using) typically have a voltage drop of between 3-5V. Assume 20mA for current - pretty standard. Function voltage should be in the neighborhood of 14-16V depending on your controller. That should get you in the ballpark.
		Gene Wolski
User Profile View All Posts by User View Thanks

JDennis		#6 Posted : 01 December 2017 02:29:36(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		No worries. Pretty obvious that the resistor needed is going to be different if the resistance of the component (LEDs in this case) is going to vary. Equally obvious that placing multiple components in series is going to change the requirement for additional resistance. Since this loco uses just one light on each end, I wasn't thinking about applications using multiple LEDs. The other tidbit of info I didn't have is that there might be different LEDs (with different resistances and different voltage requirements) available for this application. Knowing that, if I can find the specs for these LEDs, I do understand how to determine the required resistance to drop the voltage to that value for each LED. Thanks. Now, you say that the LEDs "typically have a voltage drop of between 3-5V." Since the voltage drop across each component in the circuit is a function of the circuit voltage and the resistance of the various components in that circuit, etc., am I correct that you are saying that the typical operating voltage for each LED should be about 3-5V? If that's a good general rule, and if the circuit voltage for the lighting function is going to be about 14-16V, then I can take it from there to provide the right resistance to achieve the needed drop across each LED. Thanks again.
1 user liked this useful post by JDennis		gwolski
User Profile View All Posts by User View Thanks

JDennis		#7 Posted : 01 December 2017 03:09:46(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		It was suggested that one should draw out the circuit. I'm going to try to attach my sketch. Please let me know if you see anything I missed. Enjoy.
3 users liked this useful post by JDennis		xxup, RayF, ktsolias
User Profile View All Posts by User View Thanks

Danlake		#8 Posted : 01 December 2017 03:29:51(UTC) Retweet
Joined: 03/08/2011(UTC) Posts: 1,571		Hi Dennis, I have done a few conversions and used 470 ohms resistors. It will give a bright light with a standard white 3mm LED when using a Marklin digitale controller. If you want it a bit dimmer, for e.g. a steam loco I would used a higher resistor in the region of 1k ohm. You also need to to consider the watt rating of the resistor. Smaller (thinner) resistors can handle less power and will get hot. I normally use min 0.5 watt rating. Hope this helps. Brgds Lasse
		Digital 11m2 layout / C (M&K) tracks / Era IV / CS3 60226 / Train Controller Gold 9 with 4D sound. Mainly Danish and German Locomotives.
User Profile View All Posts by User View Thanks

JDennis		#9 Posted : 01 December 2017 03:39:55(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		Thanks, Lasse. That's very useful information. This is an electric (Type 103), so I'll see how the lights look and go from there. Easy enough to swap the resistor to adjust it later. Guess I should order a variety for future use. BTW, using 2W resistors, so shouldn't have any issues there.
User Profile View All Posts by User View Thanks

gwolski		#10 Posted : 01 December 2017 14:29:56(UTC) Retweet
Joined: 17/12/2001(UTC) Posts: 171 Location: Central Virginia		One other "trick" I used with my ESU decoders is to use the additional function outputs to drive single bulbs/LEDs. That way I can configure the lighting output logically in the decoder rather than have to build supporting circuitry. A good example is Swiss lighting where all three lights are on forward and only the lower right in reverse. The lower right is a separate bulb which is basically on in both forward and reverse. The second bulb drives the other two lights. You can do something similar with different colors (red vs white) or the upper headlight (2 vs 3 lights) on the TGV.
		Gene Wolski
1 user liked this useful post by gwolski		river6109
User Profile View All Posts by User View Thanks

JDennis		#11 Posted : 01 December 2017 16:38:19(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		That makes good sense. Thanks for that.
User Profile View All Posts by User View Thanks

DaleSchultz		#12 Posted : 02 December 2017 20:34:47(UTC) Retweet
Joined: 10/02/2006(UTC) Posts: 3,997		Here you go... http://cabin-layout.blogspot.com/2017/04/led-lighting-circuits.html
		Dale Intellibox + own software, K-Track My current layout: https://cabin-layout.mixmox.com Arrival and Departure signs: https://remotesign.mixmox.com
		WWW BLOG
User Profile View All Posts by User View Thanks

PMPeter		#13 Posted : 02 December 2017 21:53:11(UTC) Retweet
Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC		Originally Posted by: DaleSchultz Here you go... http://cabin-layout.blogspot.com/2017/04/led-lighting-circuits.html Hi Dale, I usually connect my LEDs in parallel and size my resistor to get an approx. 3 V across them. In your example you have them in series. What would you say is more common and why? Cheers Peter
User Profile View All Posts by User View Thanks

kiwiAlan		#14 Posted : 02 December 2017 22:47:48(UTC) Retweet
Joined: 23/07/2014(UTC) Posts: 8,467 Location: ENGLAND, Didcot		Originally Posted by: JDennis I tried to search this but didn't find the answer I was seeking. The ESU instructions are very good and specific as to the requirement for a 470 ohm resistor when connecting LEDs with their decoders. In general I have found Marklin's documentation a bit more -- uh -- challenging. Would I be correct in my conclusion that a) a resistor is required when connecting LED lights to ANY decoder (including Marklin decoders); and b) that 470 ohms is the appropriate resistance value? Thanks. You will not blow anything up by following this advice, for any decoder. You can always increase the resistor value if you find the LEDs are too bright, but the 470 ohms will be high enough to protect the LED if there is no resistor already on the decoder. If the decoder already has a resistor then the LED may appear dim, and you may wish to reduce the value. When LEDs first came on the market the general rule of thumb (wet finger in the air ...) was 470 ohms for a 12V supply and 100 ohms for a 5V supply. LEDs these days are much more efficient at converting current into light output, so a higher resistance is often practical with a lot of people recommending values in the range of 1k to 2.2k ohms with decoders, but 470 ohms is a good all round starting value when unsure of the decoder has built in resistors.
1 user liked this useful post by kiwiAlan		Danlake
User Profile View All Posts by User View Thanks

JDennis		#15 Posted : 02 December 2017 22:57:03(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		Thanks, Alan. That all makes good sense and is very useful information. Ordered a variety of resistors from Mouser yesterday so I'll be able to adjust R as needed for the application.
User Profile View All Posts by User View Thanks

PMPeter		#16 Posted : 03 December 2017 02:03:04(UTC) Retweet
Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC		Originally Posted by: JDennis Thanks, Alan. That all makes good sense and is very useful information. Ordered a variety of resistors from Mouser yesterday so I'll be able to adjust R as needed for the application. Was I seeing things or have you changed your home state from Oregon to Minnesota?
User Profile View All Posts by User View Thanks

dickinsonj		#17 Posted : 03 December 2017 02:11:18(UTC) Retweet
Joined: 05/12/2008(UTC) Posts: 1,801 Location: Crozet, Virginia		Originally Posted by: JDennis Thanks, Alan. That all makes good sense and is very useful information. Ordered a variety of resistors from Mouser yesterday so I'll be able to adjust R as needed for the application. Lots of good advice on this forum. I usually skip the analysis and just put in 1k resistors and then adjust up/down from there as needed. I don't want searchlights in my locos, so I seldom use less than 1k. Many of the older prototypes had actual lanterns and put out very little light, and even the newer designs were not really all that bright by today's standards. I think that the tuning of those details when I do an upgrade make a loco truly mine and that it is great fun to sort all of that out and build just exactly what I want.
		Regards, Jim I have almost all Märklin and mostly HO, although I do have a small number of Z gauge trains! So many trains and so little time.
User Profile View All Posts by User View Thanks

JDennis		#18 Posted : 03 December 2017 05:46:12(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		Quote: Was I seeing things or have you changed your home state from Oregon to Minnesota? Well, if that question was directed at me, then my answers to your compound question are as follows: a) I don't know. You may very well be seeing things. I have no information on which I could base an opinion on that point. Do you have any history of "seeing things"? And b) I have not changed my home state from Oregon to Minnesota. Never lived in Oregon. Been there, but never my home.
User Profile View All Posts by User View Thanks

H0		#19 Posted : 03 December 2017 10:34:39(UTC) Retweet
Joined: 16/02/2004(UTC) Posts: 15,443 Location: DE-NW		Hi! Modern LEDs are very efficient. The TRAXX hobby locos from Märklin have three yellow LEDs in series with a 5k6 resistor. When I change them to white LEDs I add at least 10k in series, but I also tried adding 15k and 20k (keeping the 5k6 resistor). Lights are still very bright, even with a total of 25k6 ohms. With modern decoders I leave it at 5k6 ohms and dim the lights with the decoder. TRAXX conversions shown here: https://www.marklin-user...-converted-to-white-LEDs
		Regards Tom --- "In all of the gauges, we particularly emphasize a high level of quality, the best possible fidelity to the prototype, and absolute precision. You will see that in all of our products." (from Märklin New Items Brochure 2015, page 1) ROFLBTCUTS
1 user liked this useful post by H0		ktsolias
User Profile View All Posts by User View Thanks

PMPeter		#20 Posted : 03 December 2017 15:09:21(UTC) Retweet
Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC		Originally Posted by: JDennis Quote: Was I seeing things or have you changed your home state from Oregon to Minnesota? Well, if that question was directed at me, then my answers to your compound question are as follows: a) I don't know. You may very well be seeing things. I have no information on which I could base an opinion on that point. Do you have any history of "seeing things"? And b) I have not changed my home state from Oregon to Minnesota. Never lived in Oregon. Been there, but never my home. Sorry. My mistake. It was another thread where the originator of the post was from Oregon and I suggested he get his electronic components from Frys. When you mentioned Mouser, I got the posts mixed up.
User Profile View All Posts by User View Thanks

DaleSchultz		#21 Posted : 03 December 2017 15:11:19(UTC) Retweet
Joined: 10/02/2006(UTC) Posts: 3,997		Originally Posted by: PMPeter I usually connect my LEDs in parallel and size my resistor to get an approx. 3 V across them. In your example you have them in series. What would you say is more common and why? Peter 1. If you connect LEDs in parallel and one LED fails (open), all the current will suddenly go through the remaining LEDs and destroy them. 2. When LEDs are connected in series, they consume the same amount of mA as just one of them. If you connect them in parallel the mA consumed is the sum of all of them, so connecting them in series allows more LEDs for the electrical consumption.
		Dale Intellibox + own software, K-Track My current layout: https://cabin-layout.mixmox.com Arrival and Departure signs: https://remotesign.mixmox.com
		WWW BLOG
1 user liked this useful post by DaleSchultz		PMPeter
User Profile View All Posts by User View Thanks

PMPeter		#22 Posted : 03 December 2017 15:26:42(UTC) Retweet
Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC		Originally Posted by: DaleSchultz Originally Posted by: PMPeter I usually connect my LEDs in parallel and size my resistor to get an approx. 3 V across them. In your example you have them in series. What would you say is more common and why? Peter 1. If you connect LEDs in parallel and one LED fails (open), all the current will suddenly go through the remaining LEDs and destroy them. 2. When LEDs are connected in series, they consume the same amount of mA as just one of them. If you connect them in parallel the mA consumed is the sum of all of them, so connecting them in series allows more LEDs for the electrical consumption. Thanks Dale. I guess I still question why if one fails when in parallel it would destroy the others. As you point out when having them in parallel the total current draw is the sum of all of them. So if one fails wouldn't the current draw just be the current of the remaining ones? Perhaps it is at the time of failure you could have a current spike and that is what you are referring to. When in series if one fails all the others go out as well, but do not get destroyed. So then it becomes an investigation to try and figure out which one failed.
User Profile View All Posts by User View Thanks

DaleSchultz		#23 Posted : 03 December 2017 17:12:05(UTC) Retweet
Joined: 10/02/2006(UTC) Posts: 3,997		Originally Posted by: PMPeter I guess I still question why if one fails when in parallel it would destroy the others. As you point out when having them in parallel the total current draw is the sum of all of them. So if one fails wouldn't the current draw just be the current of the remaining ones? Perhaps it is at the time of failure you could have a current spike and that is what you are referring to. When in series if one fails all the others go out as well, but do not get destroyed. So then it becomes an investigation to try and figure out which one failed. if you have two in parallel using a single resistor, the current passing through the resistor is split through the two LEDs. If one LED fails all the current now goes through the remaining one and that is likely to exceed its current rating. So one dies and takes the others with it. You have to replace them all. If in series, yes, they all go out if one fails open. If it fails closed, only one goes out but it passes the current through to the rest of the string. If it fails open it is not so difficult to find which one died by applying the same current across each of them in turn by simply bridging the others out of the circuit.
		Dale Intellibox + own software, K-Track My current layout: https://cabin-layout.mixmox.com Arrival and Departure signs: https://remotesign.mixmox.com
		WWW BLOG
User Profile View All Posts by User View Thanks

PMPeter		#24 Posted : 03 December 2017 18:17:10(UTC) Retweet
Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC		Originally Posted by: DaleSchultz if you have two in parallel using a single resistor, the current passing through the resistor is split through the two LEDs. If one LED fails all the current now goes through the remaining one and that is likely to exceed its current rating. So one dies and takes the others with it. You have to replace them all. If in series, yes, they all go out if one fails open. If it fails closed, only one goes out but it passes the current through to the rest of the string. If it fails open it is not so difficult to find which one died by applying the same current across each of them in turn by simply bridging the others out of the circuit. Thanks again Dale. In my particular case I have 3 in parallel for a station platform. I am using a 910 ohm resistor which gives me 2.7 V across the LEDs and a current draw of 12.5 mA. So if one were to fail open, the temporary 12.5 mA across the remaining 2 should not cause a problem unless I am missing something. However if one were to fail closed then I would have a dead short and that would definitely cause grief in the whole circuit. This would apply if I only had a single LED. So my question becomes how do LEDs normally fail - open or closed? I guess I was trying to apply incandescent bulb logic to LEDs and that may not be correct based on what you are advising.
User Profile View All Posts by User View Thanks

DaleSchultz		#25 Posted : 03 December 2017 22:42:43(UTC) Retweet
Joined: 10/02/2006(UTC) Posts: 3,997		since you are probably running only about 4mA through each of the three LEDs, losing one (open) would only bring the others to about 6mA each and they would surely survive that current. i.e. it is only because your LEDs are being run well under their maximum current that it will probably be OK. I don't know which way they typically fail, but I know Murphy will say that it will fail in the manner most likely to result in maximum damage to other components! I found this: https://www.digikey.com/...d-preventing-led-failure Failing closed would most likely result in an abrupt increase in voltage and hopefully that would in turn burn out part of the failed LED to then bring it to an open state. All I know is when i started learning about LED circuits I read that the golden rule is never to have them connected in parallel sharing a resistor. So I don't.
		Dale Intellibox + own software, K-Track My current layout: https://cabin-layout.mixmox.com Arrival and Departure signs: https://remotesign.mixmox.com
		WWW BLOG
1 user liked this useful post by DaleSchultz		PMPeter
User Profile View All Posts by User View Thanks

JDennis		#26 Posted : 04 December 2017 00:56:33(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		Very illuminating conversation. Anybody know a source sockets for the screw-type bulb (that fit the 600100 bulbs)?
User Profile View All Posts by User View Thanks

JDennis		#27 Posted : 06 December 2017 19:16:18(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		Looking for advice/ideas on how you actually (physically) mount and wire LEDs, especially when doing conversions. For example, some Marklin locos used the bayonet style mounts (bulb 600000 I think) and some have screw in bases (used 600100 or 600200 bulbs?). Marklin sells the receptacles that accept the little two wire bulbs (socket 276770 for bulb 610080), which allows one to isolate the bulb from the chassis, but still uses an incandescent bulb. When converting a digital loco to LEDs, what sort of bases and bulbs do you use, how do you mount the lights, etc. Thanks.
User Profile View All Posts by User View Thanks

PMPeter		#28 Posted : 06 December 2017 22:01:02(UTC) Retweet
Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC		Originally Posted by: JDennis Looking for advice/ideas on how you actually (physically) mount and wire LEDs, especially when doing conversions. For example, some Marklin locos used the bayonet style mounts (bulb 600000 I think) and some have screw in bases (used 600100 or 600200 bulbs?). Marklin sells the receptacles that accept the little two wire bulbs (socket 276770 for bulb 610080), which allows one to isolate the bulb from the chassis, but still uses an incandescent bulb. When converting a digital loco to LEDs, what sort of bases and bulbs do you use, how do you mount the lights, etc. Thanks. Why not just buy the equivalent bayonet or screw base LED bulbs that are direct replacement for the 600000 and 600100 incandescent bulbs? These come with integrated resistor so you just take out the incandescent lamp and replace it with the LED bulb of the same size.
User Profile View All Posts by User View Thanks

JDennis		#29 Posted : 06 December 2017 22:09:05(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		Quote: Why not just buy the equivalent bayonet or screw base LED bulbs that are direct replacement for the 600000 and 600100 incandescent bulbs? These come with integrated resistor so you just take out the incandescent lamp and replace it with the LED bulb of the same size. Well, I do have those. And if I were leaving the loco analog/AC, that would work great. However, it's my understanding that in a digital loco the lights should not use the chassis for ground and should have independent plus and minus wires from the decoder to the light. The original bayonet-type and screw-type incandescent bulbs typically are set up with the ground side being attached directly to the chassis. So, it seems like when converting to digital (whether using incandescent or LED bulbs) one should be changing out the light mounting/wiring to isolate them from the chassis. Is that not correct?
User Profile View All Posts by User View Thanks

gwolski		#30 Posted : 12 December 2017 02:39:55(UTC) Retweet
Joined: 17/12/2001(UTC) Posts: 171 Location: Central Virginia		Originally Posted by: JDennis Looking for advice/ideas on how you actually (physically) mount and wire LEDs, especially when doing conversions. For example, some Marklin locos used the bayonet style mounts (bulb 600000 I think) and some have screw in bases (used 600100 or 600200 bulbs?). Marklin sells the receptacles that accept the little two wire bulbs (socket 276770 for bulb 610080), which allows one to isolate the bulb from the chassis, but still uses an incandescent bulb. When converting a digital loco to LEDs, what sort of bases and bulbs do you use, how do you mount the lights, etc. Thanks. I use the 276770 lamp socket that sit in the old screw in base. The LED leads fit into the bulb wire sockets, and I connect the needed resistor to one of the wire leads. I'll try to find a picture and post it later. Otherwise I simply hot glue the LEDs where needed (body shell or chassis) to shine into the headlight glazing. Heat shrink is a must to avoid shorts! Cheers!
		Gene Wolski
User Profile View All Posts by User View Thanks

JDennis		#31 Posted : 12 December 2017 02:51:21(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		Hi Gene, Yes, I've used those 276770 sockets with the 610080 2-wire bulbs, but unless I'm mistaken, that bulb is an incandescent. What I'm trying to figure out is a good approach to convert to LEDs. The tricky part, as far as I can tell, is finding something like a socket for screw-in bulbs that can be mounted in such a way that it's electrically isolated from the chassis, so you aren't using the chassis for the return/ground lead on the LED. Maybe they make an LED that plugs into those 276770 sockets, but the tricky part to that is that it would be really easy to get the bulb in "backwards." Dennis
User Profile View All Posts by User View Thanks

river6109		#32 Posted : 12 December 2017 04:50:05(UTC) Retweet
Joined: 22/01/2009(UTC) Posts: 14,874 Location: On 1965 Märklin Boulevard just around from Roco Square		Originally Posted by: gwolski One other "trick" I used with my ESU decoders is to use the additional function outputs to drive single bulbs/LEDs. That way I can configure the lighting output logically in the decoder rather than have to build supporting circuitry. A good example is Swiss lighting where all three lights are on forward and only the lower right in reverse. The lower right is a separate bulb which is basically on in both forward and reverse. The second bulb drives the other two lights. You can do something similar with different colors (red vs white) or the upper headlight (2 vs 3 lights) on the TGV. this is how I have connected them. 2 lights via F0 and the bottom right via Aux function John
		https://www.youtube.com/river6109 https://www.youtube.com/6109river 5 years in Destruction mode 50 years in Repairing mode
		WWW
1 user liked this useful post by river6109		gwolski
User Profile View All Posts by User View Thanks

JDennis		#33 Posted : 12 December 2017 04:57:42(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		Yes, I understand that, My question is about the physical installation.
User Profile View All Posts by User View Thanks

river6109		#34 Posted : 12 December 2017 05:03:13(UTC) Retweet
Joined: 22/01/2009(UTC) Posts: 14,874 Location: On 1965 Märklin Boulevard just around from Roco Square		Dennis, there are 2 type: 1 Märklin (604180) uses and another one is a standard type, usually they can be inserted into the previous bulb holder ( a bit tied sometimes) you also will find bulbs have a 360° light beam as to Led's most of them have 120° angle or less. this creates problems when you have a loco with 3 headlights, the one above never gets enough light. I make up my own little led board consisting of 3 smd led's and sometimes if there is no provision for marker lights i use white / red smd Led's, one has to remove the light defuser and than cut off very careful the end tube, I'll just put a tiny drop of superglue into the opening and than slide the tube into it. John
		https://www.youtube.com/river6109 https://www.youtube.com/6109river 5 years in Destruction mode 50 years in Repairing mode
		WWW
User Profile View All Posts by User View Thanks

JDennis		#35 Posted : 12 December 2017 05:16:35(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		The 604180 is a socket for the two wire bulbs. Have not seen LED bulbs that fit that sort of socket, but as I say, if there were a 2-wire LED, it seems it would be pretty easy to insert backwards. There are two other types of "standard" Marklin sockets: the screw-type base and the bayonet type. Both of those latter types (on the original AC/Analog locomotives) use grounded to the chassis. It is my understanding that once you convert a loco to DC/digital, the chassis should not be used to ground the bulbs (whether LED or incandescent). I have LED bulbs with screw type bases, and bayonet style LEDs So, my questions are still these: a) where do you find two wire LED bulbs that fit into the 604180 (or 276770) socket; and b) where do find screw-type sockets (or bayonet sockets) to retrofit the loco during digital conversion so as to not use the chassis for ground. Does that question make sense??
User Profile View All Posts by User View Thanks

river6109		#36 Posted : 12 December 2017 11:45:41(UTC) Retweet
Joined: 22/01/2009(UTC) Posts: 14,874 Location: On 1965 Märklin Boulevard just around from Roco Square		Dennis, there are led's with 2 wires (cathode + anode), the one which would fit most locos are 3mm or 1,8mm tower led's they fit into the socket. available from any electronic shop or ebay. the cathode (-) side this is where you add a resistor to it. you can't use led bulbs either with screw or bayonet fittings as you rightly said they are not separated from the chassis.
		https://www.youtube.com/river6109 https://www.youtube.com/6109river 5 years in Destruction mode 50 years in Repairing mode
		WWW
User Profile View All Posts by User View Thanks

JDennis		#37 Posted : 12 December 2017 14:42:45(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		OK, thanks. You say "available from any electronic shop" as if there are any electronic shops around since Radio Shack went out of business. I'll find them on line. Thanks again.
User Profile View All Posts by User View Thanks

river6109		#38 Posted : 12 December 2017 15:31:00(UTC) Retweet
Joined: 22/01/2009(UTC) Posts: 14,874 Location: On 1965 Märklin Boulevard just around from Roco Square		Originally Posted by: JDennis OK, thanks. You say "available from any electronic shop" as if there are any electronic shops around since Radio Shack went out of business. I'll find them on line. Thanks again. Dennis, I buy most of my led's from Germany and if I need quantity from China. with the current suppliers from Germany I know what I'm getting as they stock the same items over and over again. my resistors consists of 1.2k
		https://www.youtube.com/river6109 https://www.youtube.com/6109river 5 years in Destruction mode 50 years in Repairing mode
		WWW
User Profile View All Posts by User View Thanks

PMPeter		#39 Posted : 12 December 2017 16:03:22(UTC) Retweet
Joined: 04/04/2013(UTC) Posts: 1,291 Location: Port Moody, BC		I get most of my LEDs from this eBay supplier. He has lots of model railroad items and by far the best LED inventory that I have seen. kokologgo Cheers Peter
User Profile View All Posts by User View Thanks

DaleSchultz		#40 Posted : 12 December 2017 16:08:02(UTC) Retweet
Joined: 10/02/2006(UTC) Posts: 3,997		Originally Posted by: river6109 the cathode (-) side this is where you add a resistor to it. The resistor does not have to go on the negative side. It can be placed anywhere in the LED circuit so long as it is in series with the LED(s) Polarity of the current is critical.
		Dale Intellibox + own software, K-Track My current layout: https://cabin-layout.mixmox.com Arrival and Departure signs: https://remotesign.mixmox.com
		WWW BLOG
User Profile View All Posts by User View Thanks

JDennis		#41 Posted : 12 December 2017 16:44:45(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		Thanks, Guys. I've got some sources, but I do miss just being able to run up to Radio Shack for stuff like this.
User Profile View All Posts by User View Thanks

gwolski		#42 Posted : 12 December 2017 19:22:40(UTC) Retweet
Joined: 17/12/2001(UTC) Posts: 171 Location: Central Virginia		Originally Posted by: JDennis Hi Gene, Yes, I've used those 276770 sockets with the 610080 2-wire bulbs, but unless I'm mistaken, that bulb is an incandescent. What I'm trying to figure out is a good approach to convert to LEDs. The tricky part, as far as I can tell, is finding something like a socket for screw-in bulbs that can be mounted in such a way that it's electrically isolated from the chassis, so you aren't using the chassis for the return/ground lead on the LED. Maybe they make an LED that plugs into those 276770 sockets, but the tricky part to that is that it would be really easy to get the bulb in "backwards." Dennis You are correct - it's easy to get the LED in backwards, but it's easily fixed by reversing. You probably already know that, by default, the LED anode and cathode leads are different lengths so that's one way to identify which end goes where. I cut my LED leads shorter but maintain a similar slight length difference to help me know which way to orient them. If your resistor is installed, you won't blow an LED by reversing it. It just won't light up. The LEDs leads fit snugly in the socket holes - if you're worried about them coming loose, a dab of hot glue works wonders. Easily pried off if needed. I like using the socket in that I can change out the LED if I want to (e.g. warm white vs cool white). Otherwise, I don't bother with the socket but it does make for a tidy installation. Helpful?
		Gene Wolski
2 users liked this useful post by gwolski		DaleSchultz, dickinsonj
User Profile View All Posts by User View Thanks

JDennis		#43 Posted : 12 December 2017 19:26:22(UTC) Retweet
Joined: 04/11/2017(UTC) Posts: 89 Location: Minnesota		Yes, very helpful, Gene. Thank you.
User Profile View All Posts by User View Thanks

Users browsing this topic

Guest