TOPIC:

This is getting on my badword - can't see the most recent posts until I've sent a message to one of the old ones, & then I look like a pillock... So, IF you haven't already sussed this out, I would recommend you buy one of those resistor selection packs that are available from electronics stores or Ebay etc. For running LEDs off 12v, usually 1000 ohm will be about right. For 5v, start with your 1000 ohm to make sure your wiring's ok & everything works, then substitute this for resistors of gradually reducing values until you can get satisfactory brightness without the LEDs getting hot. IF they start to get hot, use a higher resistance. What I do is to use a 1000 ohm variable resistor & gradually adjust it until everything's right, then measure the resistive value I've adjusted it to, & replace it with a fixed resistor of a similar value. I wouldn't even try a resistor of 12 ohms - the resistor is about restricting CURRENT not dropping voltage

eddrick wrote:

can't see the most recent posts until I've sent a message to one of the old ones

Don't quite understand what you mean with this... is it a technical problem with the site?

Ha, I wouldn't know, I hate anything computer related, their operation is as random as that of a VCR... Basically, I get an email to say there's a new post, I click on the link & Tamiyabase displays a forum page. I look at the last comment & reply to it, the screen refreshes & I'm presented with a pile of much later posts. It might just be me/my location - always had problems with the Hilgay time-rift....

eddrick wrote:

This is getting on my badword - can't see the most recent posts until I've sent a message to one of the old ones, & then I look like a pillock... So, IF you haven't already sussed this out, I would recommend you buy one of those resistor selection packs that are available from electronics stores or Ebay etc. For running LEDs off 12v, usually 1000 ohm will be about right. For 5v, start with your 1000 ohm to make sure your wiring's ok & everything works, then substitute this for resistors of gradually reducing values until you can get satisfactory brightness without the LEDs getting hot. IF they start to get hot, use a higher resistance. What I do is to use a 1000 ohm variable resistor & gradually adjust it until everything's right, then measure the resistive value I've adjusted it to, & replace it with a fixed resistor of a similar value. I wouldn't even try a resistor of 12 ohms - the resistor is about restricting CURRENT not dropping voltage

hey i dont know why you are getting upset, 1 person tells me one thing, another person disagrees and you are shouting at the website? i dont understand this led stuff all i want is an answer to my question , not an internal forum fight

Okay, thanks for the explanation eddrick. I know what is happening and it is because the topic is quite active.
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Appreciate you're trying to help out here.

Noo noo, don't get me wrong, I'm not getting upset with anybody, just having frustrating issues with the way my PC is making me look like a div at the minute! Bottom line is, I'm not up to date with all this chat room, mug-book etc mallarky (Not really got any interest in social networking). The only real reason I keep tabs on this site is because I see people needing help with stuff I know I can help them with. It's in my nature to help people if I can. I saw I had a "connection request" from you, I've no idea what "connection requests" are all about, or what to do with it. I suspect there will be some kind of explaination somewhere, but I haven't got time to look just at the minute - I should be in the shower or feeding myself, or going to bed or something.... So, if it appears I'm being unsociable, I'm probably not, it will be more a lack of understanding of how these things work! As I said before, with my lack of computer ability, your best option for help from me would be to email me & I'd send you some info, sketches, instructions etc etc. At this point, I really have to apologise to anyone/everyone who may have read the post (Or any previous) from me & taken offence - believe me, none was meant!

Much easyer to use a led calculator to find the right resistor, instead of fidling with diffrent leds...

www.hebeiltd.co...calculator

It can be, depends where you are & what's in front of you though - I'm usually at the bench surrounded by components & it's usually quicker for me to fiddle with components than try to locate my calculator or convince the PC to boot! Also, for someone who is learning about something like this, they could prod buttons on said calculator & not know what the answer means, or spot if the answer isn't something reasonable/expected, if you get me. Handy link, I'll have to make a note of that one! Another thing to watch, that recently tripped me up, is that different brightnesses & colours can use considerably different amounts of current & require different values of resistor to the theoretical value, particularly with the newer high-brightness white ones. Sort of takes you back to trial & error with what's actually in front of you, unless you know the exact spec of that actual component

I allways seems to buy a pack of led's in one of the hardware stores here in town and all of them states clearly what they currents are, voltage and and mcd (brigthness), and I still leave them in the pack if I use 2 out of the 5 or 10 in the pack.

Same if I buy led's on ebay etc, so for me there are more handy to use the calculator online to find what resistor(s) you'll need.

And as a general rule, the most of the led kits out there on the market today use 20.000mcd as white headlights.

So if you go to your local hardware store or electrian shop, don't expect the pack with 8000mcd led's to be as bright as the led kits you can buy in the hobby shop.


But I have to say I totally understand if you have 100s of leds infront of you and haven't a clue what spec they are, it may be easyer to just try several resistors to get the effect you want..


But as a tumb rule you can say this is the most common spec on leds:

5mm hvite leds - 20.000mcd - 3.2-4V - 30mAh
3mm red - 4-8000mcd - 2-2.5V - 30mAh

But there are a HUGE amount of diffrent spec on leds out there incl colors, so just use the above info as a general info..

You can also get "VARM WHITE" leds if you don't want the exenon light effect but the classic bulb light..


Right now I have 7 cars/trucks and 4 trailers with led lights:P

Cool, although it's not really my thing I like to see trucks etc with all the detailing & lights - I appreciate the work that goes into them.
Ha, LED specs - mine are sorted as "From Sony VCR, From disposible lighters, Bits of car stereo EQ..." etc! Nope, I really don't have a clue what the ratings are!