| 摘要 |
PURPOSE:To turn ON light emitting elements with relatively small power consumption at high luminance, by continuously outputting driving signals at a potential level different from a rectangular wave signal from the output ports of a microprocessor, and conducting the light emitting elements. CONSTITUTION:A waveform shaping circuit 2 outputs a rectangular wave signal Sa (high level signal) at a duty ratio of 50% in synchronization with the output waveform, especially its positive half-wave output waveform, from a commercial AC power source through the output terminal of the circuit 2 (collector of a transistor 3). The rectangular wave signal Sa is imparted to a bus line 7. A microprocessor 1 uses the rectangular wave signal Sa as a clock signal for a timer element. The signal is also utilized as a timing signal for zero-cross switching of a switching element for turning ON and OFF a fan motor. Light emitting diode 16-19 and 21-24 are lighted only a period when the rectangular wave signal Sa at the duty ratio of 50% in synchronization with the positive half-wave output waveform of the commercial AC power source is outputted. |
