Automatic dimming curtain circuit

Published:2011/7/2 4:23:00 Author:John | Keyword: Automatic dimming curtain | From:SeekIC

When the outdoor light enhances, the interior light also enhances and the photodiode resistance becomes smaller. Then the point A’s potential rises to drive the output potential to rise on KD28’s pin 3. Besides, the potential on pin 5 decreases to drive the motor M to transfer. Afterwards, the curtain slowly closes until the indoor light weakens. The resistance of D increases until it is large enough to drive the bridge to be balanced again. Conversely, when there is less light, the motor M rotates reversely to drive the curtain to slowly open. C1 and R6 operate with delay effect. This can make the control process undergo gradually, thus being able to avoid motor’s repeated starting because of the accidentally opened curtain from wind blowing.



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