I've got this schematic for a very small lighting setup for my basement. The goal is to have two fixtures that have red, green, and blue lights that can be controlled with knobs on a Separate controller, (one brightness knob for each color on each fixture) and also a set of white LEDs in each fixture that can be strobed at different speeds (one brightness knob and one speed knob). The plan is to use potentiometers for all the brightness and have the output of each go to 4 LEDs in parallel with a resistor for each one. For the strobe I was going to use a 555 astable circuit with a very small capacitor so it goes fast, then link the output to a transistor so to impose the on/off signal to the output of a brightness potentiometer.

Any help with why this wouldn't work, what pots to use, or how to hookup the transistor right would be great.

LEDs are rated to have a 200 ohm resistor at 9 volts, Thats all I know.

Here is a rough sketch of the schematic.

Lights schematic

  • 2
    \$\begingroup\$ You probably should add a description or preferably a datasheet link for the LEDs you're planning on using. Most standard pots only like to dissipate around 200mW and wirewound tend to get expensive so that may be an issue depending on the LEDs. \$\endgroup\$
    – PeterJ
    Feb 20, 2013 at 6:24

1 Answer 1


the upper left corner would seem to indicate that you have common cathode and anode led's as in both ends are bused together, this will not work.

you probably want to have a transistor controlling the common part which will act like a "LED Select" then the non-common legs of each diode can be tied together as color select.

basically as if you were controlling a bank of 7 segment LED char displays... only just 3 segments... this will also allow you to use different resistor values for each of the diodes, because they usually have different electrical characteristics.


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