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Circuits > Motor, light and power control > 12 Volt Lamp Dimmer
12 Volt Lamp Dimmer
Here is a 12 volt / 2 amp lamp dimmer that can be used to dim a standard 25
watt automobile brake or backup bulb by controlling the duty cycle of a astable
555 timer oscillator. When the wiper of the potentiometer is at the uppermost
position, the capacitor will charge quickly through both 1K resistors and the
diode, producing a short positive interval and long negative interval which dims
the lamp to near darkness. When the potentiometer wiper is at the lowermost
position, the capacitor will charge through both 1K resistors and the 50K
potentiometer and discharge through the lower 1K resistor, producing a long
positive interval and short negative interval which brightens the lamp to near
full intensity. The duty cycle of the 200 Hz square wave can be varied from
approximately 5% to 95%. The two circuits below illustrate connecting the lamp
to either the positive or negative side of the supply.
12 Volt Lamp Dimmer circuit
Title: 12 Volt Lamp Dimmer
Source: unknown
Published on: 2007-07-21
Reads: 1380
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