An electronic watch utilizes an alternating current unidirectional induction stepping motor for electromechanical conversion. The motor is driven step-wise by an oscillator, a frequency-reducing divide circuit and a polarity reversing driver circuit. The stepping motor includes a rotor having a multipole upper disk, a multishoe bottom disk, and an axially magnetized cylindrical magnet separating and magnetizing the two multishoe disk. The stator has pole portions cooperating with both upper and lower disks.
An electronic timepiece comprising a means for generating a base signal, an electromechanical transducer to convert the base signal into mechanical motion of a rotatable shaft, only a back side chain of wheels and a driving means whereby the back side chain of wheels is directly driven by the rotatable shaft. Furthermore, the driving means is coupled to the rotatable shaft such that idling rotation of the driving means occurs without rotation of the rotatable shaft when the timepiece is being set externally.
A motor driving circuit comprising a pulse generating circuit for generating plural types of pulse trains, a modulation pulse generating circuit connected to the pulse generating circuit, a semiconductor driving circuit connected to an output of the modulation pulse generating circuit for providing operating power to a motor winding, a detecting circuit connected to the driving circuit for detecting a voltage induced in the motor winding, and a counting circuit connected to the detecting circuit. The detecting circuit has means for setting reference levels, detects the voltage induced in the motor winding in accordance with the reference levels during the time the semiconductor driving circuit is non-conducting, and sends control signals for regulating a next produced modulation pulse width to the counting circuit, and the modulation pulse generating circuit shapes the modulation pulse from the plural types of pulse trains of the pulse generating circuit in accordance with outputs of the counting circuit so as to drive the motor uniformly.
An electronic timepiece comprising a step-motor including a stator and rotor is disclosed. The timepiece is so constructed and arranged that a coil winding core of the stator is located between the stator and a dial of the timepiece and that said stator is disposed on said coil winding core.