| 摘要 |
1426231 Automatic control of speed CANON KK 25 May 1973 [25 May 1972] 25281/73 Heading G3R The speed of a D.C. motor 1 is controlled by varying the duration of pulses produced in response to a speed error signal derived from a comparison made in differential amplifier 7 of the voltage generated by tacho-generator 2 and a temperature compensated reference voltage at point F. A switchable potential divider chain 10 allows the controlled speed of the motor to be changed. The error signal produced at the collector of transistor 45 in differential amplifier 7 is applied to the base of a further differential amplifier 5 so that the saw-tooth waveform generated by unijunction transistor oscillator 6 can be sampled to produce constant amplitude pulses whose width is proportional to the error signal. In alternative constructions a triangular or sine wave oscillator can be used. The motor is used to drive the film in a cine camera. |
