Circuitry 101: How to Hook Up LEDs

I WILL NOT ACCEPT LIABILTY FOR ANY PERSONAL INJURY OR LOSS AND I TAKE NO RESPONSILITY IF YOU DAMAGE YOUR MODEL, YOU DO THIS ENTIRELY AT YOUR OWN RISK! IF YOU HAVE ANY DOUBTS IN YOUR MIND THEN CONSULT AN ELECTRICIAN. LED LIGHTS RUN COLD, BUT RESISTORS DONT THEY CAN GET HOT SO REMEMBER THIS WHEN PLACING THEM. SEE ADMIN REPLY IN THIS POST ABOUT THERE LIABILTY.

Below I've created a very basic guide to help people unfamiliar with circuits get their LEDs up and running without blowing them out and wasting all their money. IT IS VERY BASIC!! Current is hardly ever mentioned, not because it's not important, but because I've found it makes things confusing when trying to teach people about this sort of thing. If I've done a bad job explaining things or if you have a question this doesn't answer, hit the reply button and I will see what I can do.

There's two basic types of circuits: Series and Parallel.

Series or "How do I power lots of LEDs off a higher voltage source?"

When LEDs are placed in a series, the voltage is dispersed between the LEDs, meaning less voltage goes to each LED. This can be very useful. For example, if a 12 volt adapter were powering one LED, there'd be 12V going through that LED which is way too much for any LED to handle and would result in a rather unpleasant burning smell.

However, if you take that same 12V power source and put 4 LEDs in series, there would be 3V going to each LED and (assuming the LEDs are made to run off 3V) each would be powered and just dandy. Check out this illustration:



It's important to notice how the LEDs are positioned: (-) (+), (-) (+), etc. making sure that the end (-) connects to the (-) wire and the end (+) connects to the (+) wire, if any LEDs are backwards nothing bad will happen, they just won't turn on.

If three LEDs were in series with a 12V source, each would receive 4V, if six were in series, each would receive 2V, etc.

"But what if I have four LEDs powered from a 12V source and I want each to receive less than than 3V/ea?" This is where the little 'Resistor(s)' squiggly comes in. By adding a resistor it's possible to tone down the amount of voltage each receives. To find out what value resistor you should use, use an led calculator such as this one . Go to the middle form where it says 'LEDs in series' and simply type in your power sources' voltage, the LEDs' voltage you'd like and the LEDs current capability (use 20mA.) It then tells you what ohmage resistor to stick in the circuit.

But if one blows, they will all go out thats why I prefer to wire mine this next way!!

Parallel or "How d o I power lots of LEDs off a lower/higher voltage source?"

Let's say you wanted to power three of your brand new LEDs off a 3V battery pack (two 1.5V AA's in series, make sense?) you found lying around. If you were to series the three LEDs there'd be 1V going to each (3 Volts / 3 LEDs = 1V for each LED). That's not enough to power your LEDs! You want them to have the full 3V going to each. Here's how:




How this works is that while every LED receives the same amount of voltage, the current of the source is dispersed between the LEDs. What this means for you is that you have 20 LEDs paralleled off a battery, it's going to drain the battery a lot quicker than if you only had 2 LEDs in parallel. If you're paralleling off a wall adapter, for instance though, the source can constantly renew itself so you can essentially parallel as many as you'd like without fear of draining the wall .

To use resistors in a parallel circuit, say if you'd like each LED above to receive 2.5V instead of 3V, use an LED calculator (make sure you're in the parallel section) to find the right ohmage and then stick it somewhere in the circuit!

"Why do the LEDs have to be the same color?" If you mix colors, say if you paralleled a red (~2.3V) and two blue (~3.5V), the blue LEDs would not light. Why's this? Because the electricity is going to take the easiest path it can to complete the circuit and in this scenario the red LED requires less energy, leaving the two blue unpowered and lonely. To fix this you would need to stick a resistor onto the leg of each LED to 'equalize' all of the LEDs. Note illustrations:





To find the resistor you'd need for each LED, use the 'Single LED' portion of an LED calculator , type in the supply voltage, LED's voltage and 20mA for each LED and there you go. Now each LED will turn on and each will receive it's desired amount of power. The resistors act like 'shocks' in a car, they give the power source some 'squish' and let each LED find its happy place (forward voltage).

Hope it all makes sense!!!

Forgot to mention the figures in the last picture in (??? Ohm) is the actual Ohmage!

same here no pic

can see them now thanks matey

Thanks RussG, The Pics are showing at my end as well. now all i need to know is how many i need. was thinking one for each cannon and 2 or 3 for the back end, lol

Thanks for the post Russ.

Just wanted to post a disclaimer here!

We don’t endorse adding any LEDs or carrying out any electrical wiring to the model, so if you do choose to post or follow your own instructions then we can’t accept liability for any personal injury or damage to the model.

If others follow the instructions, again we cannot accept liability for any personal injury or damage to the model.

Cheers

Admin

admin get used to it pal, your gonna get an awful lot of this going on,just wait till the gunpower recipe starts doing the rounds, you will have heart attack.

Cheers Russ, as they say in the TV ad "it's simples".
Admin? Don't worry so much, you'll live longer. It's only low voltage. I used to strip live 12 volt wires, on my model railway, with my teeth. It tickled and I still got most of 'em. DON'T TRY THIS AT HOME FOLKS.

By the way I've just been to:
www.component-shop.co.uk
Seen lots of goodies like LEDs and optic fibres from 0.75 mm dia. plus some useful hints and ideas, such as "useful for getting points of light to inaccessible places", "nick the fibre at any point light is required" and, fibres are supplied in continuous lengths and charged by the metre (45p). LEDs are as little as 2p each when buying 100.[thumbs up]
I think this is just what we are looking for. The LEDs run cold, (no fire risk Admin) and we can produce lots of light points from 1 LED and a length of optic fibre that can be easily disguised as rope. (not so much wiring or risk of electrocution,no tickles Admin) Just what the Ships Surgeon ordered!

Happy lighting

Sounds like a better idea than led's we just need someone now that has used this method to answer questions like: would 1 lenght of fibre optic cable nicked at desired intervals light up a complete row of Gunports???
and the good thing is you dont have the problem of having to replace a bulb risking damaging the ship
Allan

Well iam going to play it safe and get my pal who is an electrician to do this for me, at what stage of the build do i start thinking about the fitting of the leds russ or will you be sending pics as you go . my pal will only hook up the electrick and will not place the wiring for me. thanks R.

If anyone is on a tight budget you can strip down an old fibre optic Christmas tree as they have a lot of FO strands

Allan