| 摘要 |
A circuit 62 controls a direct-current motor (not represented) so that its output shaft recopies a speed represented by a signal VC. A circuit 63 detects a possible blocking, on starting, of the output shaft, so that, in the event of blocking, a DC-voltage VB of sufficient value to unblock it is applied to the motor. A circuit 64 detects the start of rotation of the motor so that the output voltage from the control circuit 62 is then applied to the motor. Hence, the motor, without being over-large, can cope with significant variations in the load on its output shaft. The invention applies especially to recopying the rotational movement of a wheel of a motor car for displaying its speed and totalising the distance covered. <IMAGE>
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