High/Low light LED switch


I recently purchase some 3528 300p LED Strip Light so that I can make some under cabinet
lighting. I wanted to make my own because I believe I can to it for a much better price
and learn something in the process rather than buying an LED light set from a big box
retailer.

I have a 3 position rocker switch Off/high/low. If possible I would like to use the LED
lights in a High/Low configuration. From what I read they make PWM modules that control
the LED making them appear to be dimmable, but I do not want to use one of these devices.

For the low setting I was considering wiring in a POT or an inline resistor to drop the
Voltage to the LED's. On second thought I suspect that this would not work and if I drop
the voltage too low this would result in inoperable LED's. By the way I would not be opposed using an inline resistor if this is a good way to reduce the light level

Is there some cheap electronic component that will produce or simulate an approximate 50%
PWM that I can wire inline with the switch, in effect producing a low lighting mode? I
am not interested in using a variable PWM control, I just want to achieve a switchable
high/low lighting. I am not familiar with components and I hope you could suggest a few
ideas for my project.

Some details: The led strip will be ~11 linear ft using 12VDC and about 40W of
electricity.


yokozuna6 years ago
I'm always in favor of keeping it as simple as possible. Instead of trying to dim the LEDs, what if one setting only lit every other LED?
baudeagle (author)  yokozuna6 years ago
The LEDs are already pre-wired in series. I bought a pre-wired LED strip. It has 300 LEDS and I will only be using ~200 of these under the cabinet. Otherwise a good idea.
See what effect putting them in series and parallel has. Failing that, put a circuit like this in, and wire a fixed resistor where the pot is, switched by your hi-lo-off switch.

trimmable current source.JPG