A circuit for a clock having a time indicating mechanism is connected to regulate the driving of a DC motor by a predetermined amount at predetermined time intervals, so as to actuate the time indicating mechanism without being affected by the variation in the amplitude of the DC energizing voltage available for driving the motor and the variation in the load on the motor. The motor driving circuit has a timing pulse generating circuit for generating timing pulses at the predetermined time intervals, a holding circuit actuated by the timing pulse applied thereto by the timing pulse generating circuit so as to be self-held thus enabling the motor to be energized from the DC energizing voltage, and switching means, connected to the motor or the time indicating mechanism so as to be actuated when the motor is driven by the predetermined amount. The switching means is connected to the holding circuit, so that the holding circuit is deactivated to terminate the self-holding when the switching means is actuated upon completion of the driving of the motor by the predetermined amount, thereby also terminating the energization of the motor from the DC energizing voltage.
The electric motor in a digital time piece is driven in accordance with a pulse width modulated signal by supplying the signal first to a logic circuit together with the output signal from a switch which is periodically opened and closed as the motor rotates. Application of a pulse to the logic circuit begins motor rotation which does not stop until the switch is tripped.
In an analogue electronic timepiece having a transducer comprising a rotor, a stator and a driving coil, means is provided for supplying to the driving coil, periodic pulses of a selected width to drive the rotor. The width of the pulses is automatically controlled according to the load of the transducer so as to reduce power consumption and accordingly to increase the useful life of the battery by which power is supplied.
