| 摘要 |
PURPOSE: An indicating device for the completion of a warming-up is provided to inform a driver of the completion of the warming-up by measuring the voltage of an engine rpm(revolutions per minute) through a frequency converter inside a tachometer. CONSTITUTION: An rpm sensor(100) consists of an ignition coil(110) comprising a first and a second coil and boosting input current with low voltage; a distributor(120) distributing high voltage into a spark plug(125); and a tachometer(130) converting the frequency of first voltage to an effective value. The tachometer consists of a low band filter(131) passing through the low band of first voltage from the ignition coil; a transistor switching depending on bias voltage from the low band filter; a condenser charged or discharged according to the operation of the transistor; a gauge(133) indicating an engine rpm with the effective value while discharging the condenser; and diodes preventing inverse current from flowing to the gauge while discharging or charging the condenser. A comparator(200) contains an inverse current prevention diode in an output terminal and a switching unit(300) consists of a function switch(310) manually operated, an AND gate operated by the mode of the ignition switch and a relay device turned on and off by the motion of the function switch and the AND gate. An indicating unit(400) consists of an oscillator(410) generating electric continuous vibrations and a horn(420) generating an alarm sound according to signal current from the oscillator.
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