| 摘要 |
<p>The control circuit (19) receives a supply voltage (Vb) provided by a battery (7), and in response to a time-base signal (S3) it sends driving voltage pulses (Vm) to a stepping motor (5), the rotor of which causes the time (6) to be displayed. The driving pulses are also applied to the control circuit (19) which comprises an adjusting circuit (20), the function of which is to compare the voltage (Vm) of these pulses with a reference voltage (Vr) and to produce, in each pulse, interruptions, the duration and number of which are determined so as to keep the mean voltage of each pulse constant in the presence of a variation of the supply voltage. Under these conditions, the motor (5) is controlled by driving pulses of constant energy, whatever the voltage (Vb) of the battery (7). <IMAGE></p> |
