| 摘要 |
PURPOSE:To unnecessitate the use of a mechanical supplementary device such as a tachometer-generator and the like for speed detection of the titled motor by a method wherein a speed signal is obtained by sampling the motor counter electromotive voltage of the non-pulse energized section. CONSTITUTION:A timing circuit 6 generates a differential pulse b at the fall point of the pulse a which will be outputted by a pulse oscillator 5. The transistor 7a located on a waveform generating circuit 7 is put in a conductive state in synchronization with the differential pulse b, and, as a result, the transistor 4a to be used for resetting a sample holding circuit 4 is turned to a non- conductive state. When the transistor 4a is non-conductive, the counter electromotive voltage of the motor 1 is applied to a capacitor 4b. A comparator OP1 gives to a switching transistor 2 the control signal of the pulse width in proportion to the level difference between the delta wave, which is in synchronization with the pulse (a) outputted from the waveform generating circuit 7 and the voltage of the capacitor 4b. |
