| 摘要 |
PURPOSE: A brightness controller of a display unit in a washing machine is provided to improve the quality by varying the brightness proportionally. CONSTITUTION: In a peripheral illumination detector(10), a resistor(Ra4) from a constant voltage power terminal is connected with a photoelectric element(CDS). A dividing point of two resistances is connected with an A/D input terminal of a microcomputer(M). A condenser(Ca1) is connected with a ground. In a voltage controller(20), a DC output of a power unit(P) is connected with a transistor for amplifying voltage(Qa1). An output of the transistor is connected with a drive power of a display unit(D). A control output terminal(P1) is connected with a non-inverse input of a comparator(OP1) through a resistor(Ra1) according to a peripheral illumination of the microcomputer. The control output terminal is connected with a base of the transistor(Qa1) through resistors(Ra2,Ra3). An output of the comparator is fed back the non-invert input terminal.
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