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Car dome light dimmer explain the principle

2014-12-09 02:41  
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This article is a car dome light dimmer explain the principle. The combination of text read schematics would be more effective to grasp this principle. Normally, when the door is closed, dome light turns off. This circuit, you can have our ceiling slow decline in brightness and the last to leave. This slow dimming of the light gives a nice feel in the evening. This circuit can be explained as follows: When the door is opened, the door of the switch, so the cost is 22 uf capacitor completely. The opamp as a voltage follower, the output of the same voltage, the capacitor, which is 12 v When the capacitor is fully charged. Due to the high voltage output of integrated circuits, transistors saturated hydrocarbons, open the lamp to maximum brightness. Now, when the door was closed, the door switch is pressed switch failure, therefore. When the switch is off, the capacitor begins discharging slowly through VR1 and 10 k resistor and voltage gradually decreases. Therefore, the output voltage of the IC 741 is gradually reduced, thus reducing the base current of the transistor. This creates a slow decrease current through the lamp and lamp weakened, and finally when the capacitor is fully discharged, the lamp goes out. After building the circuit to promote the position of the switch (do not push in) the door is open, adjust preset VR2 to the required initial brightness of the bulb. And then press the switch in the off (or closed) and adjust the time zone VR1 maximum brightness of the lamp. I suggest you set VR1 and VR2 to their maximum. Note: 2N3055  power transistor requires an appropriate heat sink. If you are the first to understand this principle, we might Duokanjibian. The principle is simple but effective.
 

Dome light dimmer for Cars

Dome light dimmer for Cars

VN:F [1.6.9_936]

 


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