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Topic: Variable DC (Read 933 times) previous topic - next topic


Hello all,

I need a simple way to dim some 12vdc lights manually. I tried a few AC dimmer switches (the ones that are usually used for house lighting), but I couldn't get any 12vdc to flow through them.

This is probably a really simple/stupid question...but are there special DC dimmer switches?  :smiley-red:



High-power Potentiometer or Rheostat, that can handle the load (amps)?


are there special DC dimmer switches?

Yes they are used for dimming LEDs. You can get DC SSRs and feed them with a PWM signal from the arduino.

The normal mains dimmers will not work on DC as they require the fact that AC goes to zero volts twice a cycle to turn them off. This is because they use a Triac.



You need power transistors and Arduino PWM to dim 12 volt lights..

Here's an example: http://arduino-info.wikispaces.com/ArduinoPower (near the bottom)

Here's a photo:

There is example arduino dimming code at bottom of that page...
Regards, Terry King terry@yourduino.com  - Check great prices, devices and Arduino-related boards at http://YourDuino.com
HOW-TO: http://ArduinoInfo.Info


Thank you all for your replies, they are much appreciated!

I just need a simple solution this time, so I went with an adjustable 100w power resistor capable of handling the 80 watts of lighting. Rheostats at that power rating are far too expensive for me.

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