Dimmer for LED Strip Lights?

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Old 10-25-13, 09:26 AM
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Dimmer for LED Strip Lights?

I was wondering if someone could guide me in the direction towards choosing an LED dimmer for the lights I have in my kitchen. While I like the look of lights under the cabinets, they're simply too bright and I would like to turn them down if possible.

There are four 24-inch strip lights along with one puck-shaped unit installed in my kitchen. They're all wired together down to my basement where they plug into an outlet. This outlet is controlled via a light switch in the kitchen. When the light switch is flipped on, the outlet is powered and the lights are turned on.

I did buy something at Home Depot which I installed in the basement. The lights plugged into this dimmer and the dimmer would then plug into the outlet. However, it didn't work. It made a buzzing sound and the lights wouldn't dim, but as I slid the dimmer down to the off position, the lights would turn off. So they could go either on or off but nothing in between.

Below is an image with the strip lights, the puck light, the wiring and outlet in the basement, and the dimmer I purchased from Home Depot that wouldn't work. Any help would be appreciated. Thanks!

 
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Old 10-25-13, 10:38 AM
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AFAIK, not all LEDs are dim-able. Did the packaging on your lights indicate that they were dim-able?
 
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Old 10-25-13, 01:05 PM
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You might have luck with a PWM (pulse width modification) dimmer. To dim the lights it rapidly turns the power on and off. The more time off the dimmer they appear. It's all done at high frequency so your eyes don't see the flicker but it "appears" dimmer. And, since the LED's get full power during the on cycle so they have worked with every LED light I've tried when installed on the low voltage side. Here is one available online but you may be able to find them at your local home center.
 

Last edited by Pilot Dane; 10-25-13 at 01:06 PM. Reason: punctuation
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Old 10-25-13, 04:56 PM
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I didn't buy or install the lights so I have no idea whether they are dimmable.

Thanks for the tip on the PWM. I can't find one locally so I'll have to order one online.
 
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Old 11-01-13, 01:11 PM
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So I bought a PWM dimmer exactly the same as the one you linked but I'm a little confused as to how to wire it. I know that it has to go between the transformer and the lights. However, the confusing part is that the LEDs upstairs are wired with what I guess is phone wire (?) a thin brown wire with red, black, green, and yellow wires inside of it. The PWM dimmer only has slots for two wires, if red is positive and black is negative, what happens with the green and yellow?
 
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Old 11-01-13, 01:23 PM
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You have to look at what colors are connected to the lights if plus and minus aren't marked on the driver.
 
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Old 11-01-13, 01:35 PM
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Here are the wires:



Here's the dimmer:



Let's say green and yellow are positive and red and black are negative, would I put both the green and yellow wires into the positive output and the red and black into the negative? Confusing.
 
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Old 11-01-13, 03:01 PM
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It looks like someone paralleled the green and yellow into one conductor and the red and black into the second conductor.
 
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Old 11-01-13, 03:23 PM
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Treat each pair as one wire. Hopefully you can look at the LED's and see which pair they used as + and which as -.
 
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Old 11-02-13, 06:38 AM
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OK, thanks. The only hurdle now is figuring out which is positive and which is negative. Nothing is marked.

Well I pulled down some of the wires from the LEDs in the kitchen and one of them had gray dashes on them. Of course this doesn't indicate positive or negative, but it's something.

 

Last edited by iliketodiy; 11-02-13 at 06:53 AM.
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Old 11-02-13, 06:49 AM
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If the lights work use a multimeter to determine polarity.
 
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