| 摘要 |
PURPOSE: A brightness control circuit of a monitor is provided to enlarge a cutoff area by improving a brightness control circuit of a monitor. CONSTITUTION: A brightness control circuit of a monitor consists of a first transistor(Q1) having a base terminal receiving a brightness control signal from a microcomputer(MCU) and an emitter terminal grounded via a resistor(R3), a second transistor with a base terminal connected to a collector terminal of the transistor and an emitter terminal connected to a power supply via a resistor(R4), a resistor(R1) connected to the base terminal of the first transistor and grounded via a diode(D1), a resistor(R2) connected to the power supply and connected to a collector terminal of the second transistor via a diode(D2), plural voltage distributing resistors(R5,R6,R7) and a diode(D3) connected to an output terminal for feeding DC voltage to a grid(G1). The circuit includes an additional resistor(R10) between the power supply and the base terminal of the first transistor. The changing area of output voltage is enlarged by time constants of the resistors(R10,R4). Thereby, the cutoff area is extended.
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