I have a 12V DC motor that I want to power alongside a 40 Watt incandescent bulb (I might find an LED bulb that works aesthetically).  I need to run a single cord to power both.  Preferably with a dimmer and power switch in line.


With almost no wiring background, I find the lack of a Radio shack alarming! 


What resources are there to understand basic wiring fundamentals and best practice? 

What do you guys recommend in terms of attaching wiring to components, splitting the wire, and possible AC to DC conversion?

Appreciate it!


The goal is to have this plugged into a wall outlet. The motor doesn't need to be 12v. It's just I've only found a 12v that turns slow enough. I need 2 - 5 rpm and needs to be smaller than 2 in in Dia, shaft in center of motor. I can do a higher speed motor if I can find a cheap gear reduction.

Why a lower voltage? It's apparently very difficult to find a wall socket adapter to 12v that isn't huge. 5v motor that can do the job should exist.

If anyone knows a good place for that kind of motor I am all ears :)

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    \$\begingroup\$ Does your 40 W bulb run on mains voltage (100 - 400 V, depending where you live)? If so, you can't power it from the same wire as your 12 V motor. And you probably shouldn't make a single "cord" with both 12 V and mains voltages in separate wires for safety reasons. \$\endgroup\$ – The Photon Oct 5 '17 at 18:27
  • \$\begingroup\$ I think you need a power supply to turn the ac into the 12V DC. How many amps will the motor need? The dimmer and the motor probably won't play nice, so order should be on/off switch, the tap for the power supply for the motor, the dimmer and then the bulb. Be sure to make sure that everything is unplugged before you start working on it. \$\endgroup\$ – zeta-band Oct 5 '17 at 18:28
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    \$\begingroup\$ as per The Photon, the 40W bulb will need 120 or 240 V AC. You might be able to find a nice led that runs off 12 V DC. (There must be lots of automotive lights.) \$\endgroup\$ – George Herold Oct 5 '17 at 18:57

If you have to ask about basic wiring, the answer will be to avoid mains power wherever possible. So you're looking for a 12V power supply that can supply both the motor and the lamp - say, a 12V 50W supply (4 Amps - a bit more like 5-6 amps won't hurt.

So keep everything else 12V - and add some form of short circuit protection in case anything goes wrong - the supply may have short circuit protection but a fuseholder (5A fuse) in line next to it would be a good idea too.

40W bulbs are usually 110/220V - however similar powered bulbs are certainly available for 12V, as are LED bulbs.- ask any auto parts place.

While you're there, ask about the fuseholder, spade clips and a crimp tool (often available as a kit) - this will make the wiring simpler, the spade clips will plug onto fuseholder, switches and lamp bulb holder for easy assembly and changes.


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