This is a Simple Dome Lamp Dimmer Circuit Diagram . A reading light inside the car greatly assists passengers during night, but often the interior dome lamp is too bright and distracting to the driver. A linear regulator such as a rheostat can be used to control the brightness of the dome lamp but it consumes a lot of power. Here is a dome lamp dimmer that gives you a fairly linear control over the lamp brightness from low to high intensity while consuming little power. Since it is a pulse-width modulated chopper circuit, you can also use it to dim a halogen bulb or control the speed of a mini drill, etc. Simple Dome Lamp Dimmer Circuit Diagram In the circuit, timer NE555 (IC1) is wired as an astable multivibrator to produce square wave at its output pin 3. The output of timer IC1 charges/discharges capacitor C1 via diodes D1 and D2. Adjust pot meter VR1 to control the RC time constant during the charge-discharge cycle and get the timer output with the desired pulse width. Thus the bri...