Can I control multiple dimmers with a single potentiometer?

Hey everybody!

I'm working on a weird little project, and I've hit a wall. There are five lights inside a box, all of which I want to control from a single master dimmer. I'm using 12v auto lights and sockets for the lights themselves - like these - Amazon.com: Sylvania 3057LL BP Long Life Miniature Incandescent Lamp: Automotive

For power, I am using a 500w computer power supply, which is supposedly capable of pushing up to 32A at 12v.

I got this 12v dimmer, which was rated for 8A - **broken link removed** - though I paid about 3x as much for it. :x

So, I wired everything together using a configuration like the attached image below. Basically: Power => Dimmer => Hub => 5 Lights/Switches

**broken link removed**

This didn't work. If I have the dimmer turned all the way up, all of the lights turn off and on with the switches, and all juice seem to flow fine. The problems come when I start trying to use the actual dimmer. If one or two lights are on, it will dim them from 0 to 100% without problem, but as soon as I attempt to dim 3 or more lights, something fails (presumably the dimmer) and the whole power supply shuts off. Not ideal!

My assumption is that the dimmer itself is just not capable of handling that much power. I tried to track down a 12v dimmer that would be able to handle more juice, but the only one I could find is $100 and you have to use a SPDT toggle. I really want to keep the rotary potentiometer for the dimming, and I really want to keep it set up so one dimmer is controlling all five lights.

So I came up with the idea I diagrammed out below, where basically I would use five separate dimmers, each controlling its own switch/light, but that each of the dimmers would be controlled using a single potentiometer. To accomplish this, I would just wire together the "like wires" from each dimmer's potentiometer, and wire each cluster back to a single master potentiometer. Hopefully the diagram will make this make more sense.

**broken link removed**

I guess my question is - will this work? Before I go spending $50 on four more dimmers and start cutting up the wires, I wanted to make sure this was even reasonable. Logically it seems to work for me, but there are usually factors i'm not considering. If it isn't obvious already, I'm already messing around in an area well beyond my knowledge level with all of this stuff, and just trying to figure it out as I go.

If I can't do it this way, are there any ideas for how I might be able to accomplish what I'm trying to accomplish.

Thanks for your time and any help you might be able to give me!

Jason

Have you measured the amps drawn by the lamps as you decrease the power? As the filament gets cool, the resistance decreases, and the current may increase.

You must find out how much current each bulb takes as the dimmer will only handle a total of 8A. Thats 8/5 = 1.6 A per bulb or each bulb is 12 X 1.6 = 19.2 watts.
The easiest way to extend the current rating of the dimmer, that is to slave some more power transistors to it, so each power transistor will take some of the current. You said (I think) that the dimmer will handle 2 bulbs OK. So 2 bulbs = 8A, one bulb is 4A or 12 X 4 = 48 (50) watts. So you should need three power transistors @$5 each and a piece of Ali to mount them on. BUT you need to find out the circuit of the dimmer.
Frank

Hey guys, thanks for the responses!

Below are the actual specifications for the different components I'm using...

jonw - i have not measured, but i will try to do so today

chuckey - Here is the best picture i can take at the moment (not at home) of my dimmer circuit board:



Now I just need to figure out what kind of circuit it is, what kind of transistors I would need to add, and how the heck I would go about doing that. Are there online tutorials for this sort of thing?

Thanks a lot for your help, again, I'm really in over my head on this one.

Dimmer - Working temperature: -20-60 ? ? Supply voltage: DC12V ?Output: 1 channel ? External dimension: L89 ? W59 ? H35 mm ? Packing size: L96 ? W64 ? H65 mm ? Net weight:8 5 g ? Gross weight: 10g ? Static power consumption: <1 W ? Output current: <8 A ? Max. output: 96 W -- it's this guy: Amazon.com: PWM Dimming Controller For LED Lights or Ribbon, 12 Volt 8 Amp, 3301: Home Improvement

Power Supply - DiabloTek 550Watt ATX Power Supply; High efficiency, Low Noise and Ripple Output, Over Voltage protection and Short-circuit protection at any DC output. Fans: 80mm fan; Main Connector: 20+4Pin; SATA Power Connector: 2; Input Voltage: 115/ 230 V; Input Frequency Range: 50/60 Hz; Output: +3.3V at 28A,+5V at 30A,+12V1 at 24A,+12V2 at 0.8A, -12V at 0.3A,+5VSB at 2.0A; Connectors: 1 x Main connector (20+4Pin) 1 x 4-Pin ATX 12V 4 x Peripheral 2 x SATA 1 x Floppy

Bulbs: 26.88/6.72 watt - 2.1/.48 AMP - 12.8/14 vol -- i'm using a different brand, but they are basically these: Amazon.com: EIKO 3057NA - 12.8/14V 2.1/.48A/S-8 Plastic Wedge Base: Home Improvement

I read the spec. for the dimmer and its a LED dimmer. LEDs need a constant current and their voltage depends on the current, so a LED dimmer will sense the current and reduce it as it dims. While its doing this, the output voltage will vary 2.5 ->10V !!
The bulbs you have highlighted are dual filament, 2.1 A and .48 A. How much light do you need?, cos' 5 X .48 = 2.4A rather then 5 X 2.1= 10.5A
Frank