Abstract: A method and apparatus utilizing a low voltage level actuator and a signal processing device such as a microprocessor to selectively electrically couple an electrical appliance with a switch circuit associated with a power source of relatively high voltage. The microprocessor is responsive to low level electrical signals from the actuator to control operation of the switch circuit and the appliance without posing a shock hazard to the user. One form of actuator includes a piezoelectric element.
Abstract: A circuit for causing an element to produce a substantially linear response to an input signal comprising an element for providing a response, a transistor oscillator circuit for providing an electrical output signal of variable amplitude to excite the element in response to the input signal, the transistor oscillator circuit normally causing the electrical output signal to vary non-linearly with respect to the input signal, and microprocessor means for correcting the non-linear relationship between the input signal and the electrical output signal to thereby cause the electrical output signal to vary substantially linearly with respect to the input signal when the input signal is applied to the microprocessor means.
Abstract: A crystal, which is mounted in a rotatable support for use in tuning the wavelength of an optical parametric oscillator, is maintained at a desired temperature by positioning a heating sleeve to thermally coupled to the crystal and its support in such a way that the crystal is still free to rotate. The heating sleeve has an embedded heating element for connecting to an electronic controller whose dynamic output response matches the dynamic temperature characteristics of the combination of components including the crystal, it rotatable holder and the heating sleeve, so as to quickly stabilize changes in the crystal temperature with a minimum amount of overshoot.
Abstract: A heat control and interface stress control principle for a material in which a piezoelectric member is positioned in contact with an interface of the material so that a heat generated expansion of the material generates a piezoelectric signal that controls a thermoelectric cooler in contact with the piezoelectric member.
December 18, 1991
Date of Patent:
February 23, 1993
International Business Machines Corporation
Abstract: An autothermostatic high frequency oscillator comprising a piezoelectric resonator of the type having electrodes which are not adhered to the crystal. The contact between the part of the crystal 1 serving to support the vibrating part of the crystal and the dielectric plates 2,3 supporting the excited electrodes is limited to a discontinuous surface of reduced scope constituted by a finite number of elements of contact surface. At least an infra-red reflector screen (200) located at the very interior of the water tight cavity (400) surrounding the resonator is situated immediately adjacent said resonator and the electric power applied to the excited electrodes is at least in the range of about 50 microwatts. The invention permits one to achieve oscillators with small consumption of energy and high stability.
Abstract: An improved oven (10) for maintaining the junctions of a plurality of reference thermocouples at a common and contant temperature. The oven (10) is characterized by a cylindrical body (12) defining a heat sink having an axially extended cylindrical cavity (14), a singularized heating element comprising a unitary cylindrical heating element consisting of a resistence heating coil (20) wound about the surface of a metallic spool (18) having an axial bore (22) defined therein and seated in the cavity, an annular array of radially extended bores (30) defined in the cylindrical body (12) and a plurality of reference thermocouple junctions (32) seated in the bores in uniformly spaced relation with the heating element, and a temperature sensing device (28) seated in the axial bore for detecting temperature changes as they occur in the spool and circuit (46) for applying a voltage across the coil in response to detected drops in temperatures of the spool.
February 20, 1980
Date of Patent:
April 28, 1981
The United States of America as represented by the Administrator of the National Aeronautics and Space Administration