12 volt led light

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URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=94222
Printed Date: May 28, 2024 at 8:09 PM

Topic: 12 volt led light

Posted By: fredb38
Subject: 12 volt led light
Date Posted: May 24, 2007 at 9:16 PM

Is their a way to make a 12 volt LED light dimmer. I tried a resistor which had no effect.

I have a light that contain 16 LED lights. When 12 volts is applied to the light it is very bright as it should be. I was wondering if their was someway to tone it down.

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Fred

Replies:

Posted By: KPierson
Date Posted: May 27, 2007 at 8:46 AM

You can do it with PWM (Pulse Width Modulation).

You should be able to do it with a resistor, too, but you won't get a smooth dimming.

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Kevin Pierson

Posted By: fredb38
Date Posted: May 27, 2007 at 12:01 PM

I have tried resistors with no effect. I tried 10 ohms, up to 50 ohms and it did not dim the lights at all. I measured the voltage as it did drop but still had no effect on the LEDs. The voltage started out around 12 volts and with the resistors I had it down to 10 volts but no effect on the lights.

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Fred

Posted By: KPierson
Date Posted: May 27, 2007 at 12:49 PM

You're going to need larger resistors then that, as you are trying to limit current.

If it is a 12vdc LED then has a resistor built in already. I would try something starting at 1K ohms and working up towards 10K ohms.

For a project that I completed that needed two different LED brightnesses I used 470 ohms for 'bright' and 10K ohms for 'dim'. These were standard non 12vdc LEDs though.

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Kevin Pierson

Posted By: integrapwnage
Date Posted: June 05, 2007 at 4:03 PM

Or you could goto radioshack and ask\look for a dimmer switch and hook that up so you can choose how dim or bright you want the LED's

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