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How to Dim a 12V Blue LED

LEDs (light-emitting diodes) are electronic components that serve two simultaneous purposes -- they allow current to flow in only one direction and they indicate that flow is occurring via lighting of a built-in lamp available in several colors. The intensity of an LED's brightness varies with the amount of current it receives. One way to dim an LED's light -- regardless of its color -- is to reduce its current by placing a variable resistor in its circuit. Variable resistors in electronic circuits are called potentiometers and have a control knob that allows the user to adjust the circuit resistance, controlling the brightness of an LED.

100-1000 ohm potentiometer
Soldering iron
Rosin core solder
3 6-inch lengths of copper wire

Instructions

- 1
  Turn off power to the circuit. Find the two leads of the LED in a circuit. De-solder and disconnect one lead of the LED from the circuit.
- 2
  Prepare rosin-core solder. Solder one end of a 6-inch wire to the connection in the circuit where the LED's lead was disconnected.
- 3
  Solder the free end of the 6-inch wire to the middle lead connection of a 100-1000 ohm potentiometer. A potentiometer has three leads. The center lead is negative side circuit lead. The left and right lead connections are the positive side circuit leads.
- 4
  Solder a 6-inch wire to either the left or right lead connection of the potentiometer. A right-side connection will increase the potentiometer's resistance when the knob is turned clockwise. A left-side connection will increase the potentiometer's resistance when the knob is turned counterclockwise. It's a matter of preference by the user.
- 5
  Solder the free end of the second wire to the free end of the LED. The circuit is now complete. Turn on power to the circuit. Turn the potentiometer knob clockwise and counterclockwise to adjust the LED to the level of dimness desired.

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