| 摘要 |
<p>1,175,096. Automatic control of speed. PAILLARD S.A. March 17, 1967 [April 4, 1966], No. 12532/67. Heading G3R. [Also in Division H3] The speed of a motor M is controlled by regulating the on/off periods of an electronic switch (a transistor 1) in response to the amplified difference in duration of pulses generated by a motor driven device e and that of reference pulses. As shown, the reference pulses are generated by a monostable multi-vibrator 8, 9 triggered by the output 6 of a Schmitt trigger 4, 5 which squares the pulses from generator e. The output 6 is also applied to the base of a transistor 12, the emitter of which is connected at 11 to the multivibrator so that 12 conducts only when a pulse is present at 6 and absent at 11, i.e. for a time equal to the difference in duration of the respective pulses. This difference is amplified by the circuit comprising capacitor 17; this is charged during the conduction of 12 (and 15, 16) and discharged through 19 for the remainder of the time, and a transistor 21 is conductive whenever the charge is above a low level. 21 is connected to amplifier stages 22, 23, 24 to directly control the conduction of transistor 1. Desired speed is adjusted by varying the time constant of the multi-vibrator 8, 9. Circuit 27, 29, 30 ensures conduction of 1 at starting, when pulses from e are absent. A further monostable multi-vibrator 33, 34 positively switches the first back to its stable state at the end of each pulse from the Schmitt trigger to prevent the motor being controlled at a multiple of the desired speed. The motor may drive a cine camera, and it is stated that the action of the multi-vibrator 8, 9 could be controlled by a separate signal source, e.g. to synchronize sound and vision.</p> |
