| 摘要 |
PURPOSE:To prevent from a frequency supplied to an ammeter from coinciding with a resonance frequency by providing an oscillator, the 1st and the 2nd pulse generators, selecting means, rotating speed display device, etc. CONSTITUTION:Monostable multivibrator MMs 6, 12, 14, and 18, a moving coil type ammeter 10, frequency dividing circuit 16, and a switching circuit 20, etc., are provided. When a pulse train signal Pa is supplied to the MM6, a pulse train signal Pb is outputted. When the signal Pa is supplied to the circuit 16, on the other hand, the circuit 16 outputs a pulse train signal Pc, then outputs a pulse signal Pd which is equal in duty ratio to the signal Pb through the MM18. Therefore, the signal Pd after the signals Pb and Pa are frequency-divided and a mean voltage applied to the ammeter 10 do not vary. Further, the signal Pa is supplied to the MM12 and a pulse train signal Pe is outputted. This MM12 has a retriggering function, so an H signal is outputted at any time. Thus, the MM18 outputs the signal Pd and the MM14 outputs a signal Pf, and they are outputted to the circuit 20.
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