| 摘要 |
PURPOSE:To eliminate the deflection of a pointer even in a region where the frequency of an input signal is low by multiplying the frequency of the input signal and setting the set current value in a driving circuit with a constant current pulse at half of the specified value. CONSTITUTION:The input pulse signal In which is supplied to an input terminal 1 and has the frequency proportional to the number of revolutions of an engine is multiplied with a frequency multiplier 5 and is then inputted to a monostable multivibrator circuit 2. The signal of the constant pulse width of which the period is made half of the period of the signal in the prior art is inputted from a driving circuit 3 with a constant current pulse wherein a current set value is set at half of the specified value to an analog ammeter 4. Thus, the pointer of the ammeter 4 indicates exactly the number of revolutions of the engine without deflection even if the frequency of the input pulse signal is low. |
