The piezoelectric balance spring (3) is provided for a circuit (10) for self-regulating an oscillation frequency of an oscillating mechanical system (2, 3), or an energy recovery circuit or a motor circuit for actuating the movement or for the automatic maintenance thereof. The piezoelectric balance spring (3) comprises at least one piezoelectric layer (7, 7′, 17, 17′, 27, 27′) disposed on a top face (20) or bottom face of a certain number of coils of the spring in a plane, and at least two pairs of electrodes (8a, 8b, 8c, 8d), whereby the electrodes of each pair are disposed on two opposing faces of the same piezoelectric layer or respectively two piezoelectric layers so as to apply a reverse bias voltage on each pair of electrodes.

Provided are a timepiece having a temperature compensator drivable by a low voltage with low current consumption, and a control method of a timepiece. The timepiece includes an arithmetic circuit, a first switch that controls connection of a temperature compensation table storage to a power supply circuit, and a second switch that controls connection of a device-difference compensation data storage to the power supply circuit. The arithmetic circuit calculates a compensation amount based on a temperature measured by a temperature detector, a temperature compensation data, a device-difference compensation data, and outputs to a frequency adjustment control circuit and a theoretical regulation circuit. The first switch is controlled to the connect state during a first power supply connection period including a temperature compensation data read period. The second switch is controlled to the connect state during a second power supply connection period including a device-difference compensation data read period.

Provided are a timepiece having a temperature compensator drivable by a low voltage with low current consumption, and a control method of a timepiece. The timepiece includes an arithmetic circuit, a first switch that controls connection of a temperature compensation table storage to a power supply circuit, and a second switch that controls connection of a device-difference compensation data storage to the power supply circuit. The arithmetic circuit calculates a compensation amount based on a temperature measured by a temperature detector, a temperature compensation data, a device-difference compensation data, and outputs to a frequency adjustment control circuit and a theoretical regulation circuit. The first switch is controlled to the connect state during a first power supply connection period including a temperature compensation data read period. The second switch is controlled to the connect state during a second power supply connection period including a device-difference compensation data read period.

A balance wheel including a rim connected to a hub with at least one arm, wherein the balance wheel includes an adjustable auxiliary temperature compensation system mounted in the space defined by the rim to allow adjustable temperature compensation of the balance wheel.

A bimetallic device, the difference in expansion coefficient of which is between 10 and 30 10.sup.−6 K.sup.−1, for providing a resonator with thermal compensation via the balance wheel.

A method for manufacturing a balance spring intended to equip a balance of a horological movement, including a step of producing a blank made of a Nb—Zr alloy including between 10 and 30 wt % Zr, a step of annealing and cooling the blank, at least one step of deforming the annealed blank in order to form a wire, wherein, before the deformation step, a step of depositing, on the blank, a layer of a ductile material chosen from copper, nickel, cupronickel, cupro-manganese, gold, silver, nickel-phosphorus Ni—P and nickel-boron Ni—B, in order to facilitate the wire shaping operation, the thickness of the ductile material layer deposited being chosen such that the ratio of the area of ductile material to the area of the alloy for a given wire cross-section is less than 1, preferably less than 0.5, and more preferably lies in the range 0.01 to 0.4.

Provided are a timepiece having a temperature compensator drivable by a low voltage with low current consumption, and a control method of a timepiece. The timepiece includes an arithmetic circuit, a first switch that controls connection of a temperature compensation table storage to a power supply circuit, and a second switch that controls connection of a device-difference compensation data storage to the power supply circuit. The arithmetic circuit calculates a compensation amount based on a temperature measured by a temperature detector, a temperature compensation data, a device-difference compensation data, and outputs to a frequency adjustment control circuit and a theoretical regulation circuit. The first switch is controlled to the connect state during a first power supply connection period including a temperature compensation data read period. The second switch is controlled to the connect state during a second power supply connection period including a device-difference compensation data read period.

Provided are a timepiece having a temperature compensator drivable by a low voltage with low current consumption, and a control method of a timepiece. The timepiece includes an arithmetic circuit, a first switch that controls connection of a temperature compensation table storage to a power supply circuit, and a second switch that controls connection of a device-difference compensation data storage to the power supply circuit. The arithmetic circuit calculates a compensation amount based on a temperature measured by a temperature detector, a temperature compensation data, a device-difference compensation data, and outputs to a frequency adjustment control circuit and a theoretical regulation circuit. The first switch is controlled to the connect state during a first power supply connection period including a temperature compensation data read period. The second switch is controlled to the connect state during a second power supply connection period including a device-difference compensation data read period.

A watch includes a chargeable power supply, a crystal oscillation circuit including a crystal oscillator and an oscillation circuit and configured to stop oscillating when a power supply voltage falls below an oscillation stop voltage and to start oscillating when the power supply voltage exceeds an oscillation start voltage, which is higher than the oscillation stop voltage, and a divider circuit that outputs a reference signal by dividing an oscillation signal output from the oscillation circuit. The watch also includes a temperature compensation circuit that performs a temperature compensation function operation that compensates for variation of the reference signal due to a temperature, a first voltage detection circuit that detects that the power supply voltage exceeded a first voltage that is set higher than the oscillation start voltage, and a control circuit that starts the temperature compensation function operation of the temperature compensation circuit when the first voltage detection circuit detects that the power supply voltage exceeded the first voltage, and subsequently continues the temperature compensation function operation even when the power supply voltage falls below the first voltage.

A watch includes a chargeable power supply, a crystal oscillation circuit including a crystal oscillator and an oscillation circuit and configured to stop oscillating when a power supply voltage falls below an oscillation stop voltage and to start oscillating when the power supply voltage exceeds an oscillation start voltage, which is higher than the oscillation stop voltage, and a divider circuit that outputs a reference signal by dividing an oscillation signal output from the oscillation circuit. The watch also includes a temperature compensation circuit that performs a temperature compensation function operation that compensates for variation of the reference signal due to a temperature, a first voltage detection circuit that detects that the power supply voltage exceeded a first voltage that is set higher than the oscillation start voltage, and a control circuit that starts the temperature compensation function operation of the temperature compensation circuit when the first voltage detection circuit detects that the power supply voltage exceeded the first voltage, and subsequently continues the temperature compensation function operation even when the power supply voltage falls below the first voltage.