| 摘要 |
<p>PURPOSE:To immediately inform the malfunction lighting display lighted on a meter panel on the basis of the detection of malfunction of a body to be detected. CONSTITUTION:When battery voltage is abnormally lowered, an L-level is output from an operation amplifier M2 of an abnormal voltage detecting circuit unit 7 to turn off a transistor Tr. In an oscillating circuit unit 6, a capacitor C3 is charged and discharged in reponse to the level of the output from the operation amplifier M2, namely, the L-level or an H-level, and a cycle thereof corresponds to the time constant to be decided by resistors R6, R7 and the capacitor C3 because the transistor Tr is turned off, and voltage VB of a point B is a triangular wave at about 1Hz of frequency. This triangular wave is shaped into the square wave pulse having a duty ratio corresponding to the voltage Vd from the volume control VR by an amplifier M3. This square wave pulse is output to a gate terminal of a transistor Q1 of a load drive circuit unit 10, and the transistor Q1 is turned on/off at about 1Hz of frequency on the basis of the square wave pulse to flash a meter panel lighting lamp 3 at about 1Hz.</p> |
