How to Wire

At the beginning of this learning curve, I was still thinking that I had to have a master plan such as is needed when wiring an entire dollhouse for 12 volt AC (alternating current) lights. I was stumbling around in the dark of the DC (direct current) LED system. (See box below)

Two different sources gave me a bunch of formulas about resistors, some definitions, a little discussion about GOW lights (huh?) and much more that scrambled my brains.

When I asked Shelly, “How do I wire if I am using a transformer (adapter) with DC that will plug into the wall?” she explained this way.

Parallel Diagram

Using the above picture:

You will begin with the adapter and power jack. You will connect the red wires on all your lights to the red wire coming off of the power jack. Next, you will connect one wire of the switch to the black wire on the power jack. Finally all of the black wires on all of the LED lights are connected to the black wire of the switch. Protect all connections with Shrink Tube or with Electrical Tape.

Thus, in your diagram there will be 2 lines (a red and a black) running to each LED location, coming from the one common power supply. The porch light will probably require an extra length of red wire and extra black wire in order to be hidden in its run to the porch roof. (go back a few days and take a look at the wiring plan picture)

[Note: In parallel a 3 volt light needs 3 volts, 10 of the 3 volt lights will still need 3 volts of power. A 3v coin cell battery can run ten 3 volt lights.]

[Note: A 9 volt runs 9 volt lights, a single 9 volt battery can run 50 9 volt lights. Shelly at Evan Design tested this.]

[Shelly wrote: You also mentioned resistors. Evan Design does that for you. They figure all of the necessary resistance on the lights. No one needs to know all of the math. Yay!] 

Other questions I had that I got answers to were:

1) Are there DC transformers (later learned these are also called adapters)?

Adapter and transformer are interchangeable words we use for the black box that plugs into a wall outlet and puts out a certain AC or DC voltage. [you need to buy the transformer/adapter for the system, AC or DC, you intend to install] I guess a better more general word might be power supply. But power supply implies the device gives power without the wall socket.

There is an article about power supplies here: http://en.wikipedia.org/wiki/Power_supply#DC_power_supply

This definition on wiki uses both words interchangeably:

A transformer adapts household electric current from high voltage (100 to 240 volts AC) to low voltage suitable for consumer electronics. These adapters will warm through converting between direct current and alternating current, but are safe to the environment and can withstand months of continuous activity.

2)What about those thingies that determine the direction of the flow of electricity?

This is only a problem if you are using an AC adapter. Direct current is just that, direct. It runs in a circle from the adapter out through the red wire, to the LED and back in through the black wire to the adapter.

3) Can I use the LEDs in fixtures I make myself?

If you build a fixture, all you need to consider (if using Evan Design LEDs) is if the size of the LED and its resistor will fit through the hole in the fixture. See the sizes of LEDs.

Evan Design has a size chart here:

http://www.modeltrainsoftware.com/led-sizes-explained.html  In addition, LEDs may be sanded when necessary. For example a "can" style recessed light can use a sanded-flat 5mm LED in it to defuse light and make the LED less like a spotlight.

Note: back when I knew nothing, this was part of the conversation and I only include it here in case you have the same question I had:

Should I use a battery for this type of project? A nine volt will only give me three lights (3v. each). I actually would prefer a little higher voltage lights (or is it amps?) to get the shop a bit brighter.

Here’s Shelly’s answer:

One thing we need to clear up first off!

You said 3 lights of 3 volts each can run on a 9 volt source. I believe you got that information from someone who wires LEDs in series where each LED is linked to the light next in line, and then a single red wire is linked to the power source while a single black wire is linked to the black line of the power source.

We wire in parallel not series. This means that each light (LED) has its black and red leads connected directly to the power source (adapter). We’ve tested series wiring and find that it does not work well. (see parallel diagram above)

What all this added up to for me was that I would install the power jack in the base of my building and make an easily accessible place to install the switch. I would then build the building to a certain point (leaving access for wiring) and finally make my light fixtures, holes for bare hidden LEDs and the flickering stove. Then I could run all their wires in concealed places down to the underneath of the building where I would take each black wire from all my LEDs, (as long as I did not have more than 50 bulbs) solder them together and connect them to the switch wire. Simple, simple, simple!

I would then take each red wire from each bulb, solder them together and then solder or twist the reds to the red wire coming out of the power jack. Thus I would have a parallel wiring system.

Hooray! I would not need to figure out a wiring diagram. No circuits! AND if I decide I need more lights at a later date, adding would be simple.