4091 results about "Temperature coefficient" patented technology

An electrosurgical medical device and method for creating thermal welds in engaged tissue. In one embodiment, at least one jaw of the instrument defines a tissue engagement plane carrying a variable resistive body of a positive temperature coefficient material that has a selected decreased electrical conductance at each selected increased temperature thereof over a targeted treatment range. The variable resistive body can be engineered to bracket a targeted thermal treatment range, for example about 60° C. to 80° C., at which tissue welding can be accomplished. In one mode of operation, the engagement plane will automatically modulate and spatially localize ohmic heating within the engaged tissue from Rf energy application across micron-scale portions of the engagement surface. In another mode of operation, a variable resistive body will focus conductive heating in a selected portion of the engagement surface.

An oscillator includes a first crystal resonator, a second crystal resonator, a first amplifier circuit for oscillation, a second amplifier circuit for oscillation, a mixer circuit, a frequency selection circuit, and a first frequency conversion circuit. Assuming that resonance frequencies of the first and the second crystal resonators at a reference temperature are respectively F₁ and F₂, and temperature coefficients expressed as a rate of change corresponding to temperatures of the resonance frequencies of the first and the second crystal resonators are respectively A₁ and A₂, the relationship of F₂/F₁≠|A₁/A₂| is satisfied. A signal with a temperature compensated frequency is obtained from the frequency selection circuit.

A method of fabricating an acoustic resonator includes forming a ferromagnetic compensator, such as one comprised of a nickel-iron alloy, which at least partially offsets temperature-induced effects introduced by an electrode-piezoelectric stack. The compensator has a positive temperature coefficient of frequency, while the stack has a negative temperature coefficient of frequency. By properly selecting the thickness of the compensator, temperature-induced effects on resonance may be neutralized. Alternatively, the thickness can be selected to provide a target positive or negative composite temperature coefficient of frequency. In order to prevent undue electromagnetic losses in the ferromagnetic compensator, a metallic flashing layer may be added to at least partially enclose the compensator.

The invention discloses a lithium ion battery internal temperature monitoring method. The monitoring method includes the following steps that a charge-discharge tester is used for carrying out charge-discharge tests on a lithium ion battery on different environment conditions to obtain a battery surface temperature change curve; related parameters such as battery internal resistance and an open-circuit voltage temperature coefficient are tested, and a lithium ion battery electric heating coupling model based on a variable heat production rate is set up; the temperature rise change of the discharge process of the battery is simulated to obtain a temperature change simulation curve; the experiment test temperature change curve and the simulation curve are analyzed and compared to optimize and verify the electric heating coupling model; the influence between the battery internal temperature and the battery surface temperature as well as the influence between the discharge currents and the discharge depth are analyzed, and a lithium ion battery internal temperature model is constructed; the battery internal temperature is monitored in real time according to the model. The lithium ion battery internal temperature monitoring method is simple and easy to implement, small in estimation error and capable of well meeting the requirement for monitoring the battery internal temperature in real time.

This invention discloses an inductor that includes a conducting wire composed of an alloy having temperature coefficients of resistance (TCR) approximately 0.0002 milliohm per Celsius degree or is lower. The inductive coil has a winding configuration provided for enclosure in a substantially rectangular box with a mid-plane extended along an elongated direction of the rectangular box wherein the conducting wire interesting at least twice near said mid-plane.

In a light waveguide circuit including a plurality of waveguides having different length, a material (10) having a temperature coefficient of a refractive index including a symbol different from that of a temperature coefficient of an effective refractive index of the waveguide (4) is charged into a groove (12) formed by removing the upper clad and the core from the waveguide (4), or a groove (12) formed by removing the upper clad, the core and the lower clad from the waveguide (4). A difference in length of the removed portions between adjacent waveguides is proportional to a difference in length of the waveguides which were not removed and remained.

MEMS resonators containing a first material and a second material to tailor the resonator's temperature coefficient of frequency (TCF). The first material has a different Young's modulus temperature coefficient than the second material. In one embodiment, the first material has a negative Young's modulus temperature coefficient and the second material has a positive Young's modulus temperature coefficient. In one such embodiment, the first material is a semiconductor and the second material is a dielectric. In a further embodiment, the quantity and location of the second material in the resonator is tailored to meet the resonator TCF specifications for a particular application. In an embodiment, the second material is isolated to a region of the resonator proximate to a point of maximum stress within the resonator. In a particular embodiment, the resonator includes a first material with a trench containing the second material. In a specific embodiment, the shape, dimensions, location and arrangement of a second material comprising silicon dioxide is tailored so that the resonator comprising a first material of SiGe will have a TCF of a much lower magnitude than that of either a homogeneous SiGe or homogeneous silicon dioxide resonator.

An electrical heater utilizes negative temperature coefficient material (NTC) and current imbalance between live and neutral ends of the heater to simultaneously protect the heater from the hot spot and mechanical intrusion into the heating cable. The NTC layer, separating the heating wire and current leakage conductor, becomes electrically conductive at the temperatures above 60° C., thus “leaking” the current to earth. The hot spot is detected by measuring the current imbalance between line and neutral connections of the heating cable. The mechanical intrusion into the heater, such as cable or insulation damage, water or sharp metal object penetration, is also simultaneously measured by the same current imbalance measuring system such as Ground Fault Circuit Interrupter (GFCI). The optional return conductor and metal foil/mesh hot spot detection shields cancel electromagnetic field. The heater may contain positive temperature coefficient (PTC) continuous sensor to control the temperature in the heater. Such PTC sensor can be made of electrically conductive fibers and/or metal wires.

A method of sensing a magnetic field including at least one magnetoresistive sensing element (100) in a circuit (101) includes supplying (702) a first plurality of currents to a stabilization line (116) disposed adjacent the magnetoresistive sensing element (100), applying (704) a second plurality of currents to a self test line (120) disposed adjacent the magnetic tunnel junction (100), one each of the first plurality of currents being supplied during one each of the second plurality of currents. Values sensed by the magnetic tunnel junction sensing element (100) in response to the supplying (702) of the first plurality of currents and the applying (704) of the second plurality of currents are sampled (706) and the sensitivity of the magnetic tunnel junction sensor (100) and electrical and magnetic offset are determined (708) from the sampled values. The temperature coefficient of offset may also be determined.

The invention relates to a high polymer-based graphene composite material with positive resistance temperature coefficient, and a preparation method of the material. The composite material comprises a base body and conductive filler; the content of conductive material is 0.01-10wt%; all components are mixed uniformly and are formed through mold-pressing or extrusion/injection molding; and the formed material is irradiated after being dried, so that the high polymer-based graphene composite material with positive resistance temperature coefficient can be obtained. Compared with the prior art, the graphene composite material and the preparation method have the advantages that the manufacturing process is simple, less influence is caused to the performance of base material, oxidation is unlikely to occur, the resistivity is more stable, the circulation stability of the material is better, and NTC (Negative Temperature Coefficient) effect is not generated easily.

Simplified laser drivers for closed path digital optical cables and digital optical cables including the simplified laser drivers. The laser driver can include less transistors than conventional laser drivers for optical communication cables. The laser can include a bias source and modulation source. The bias source can have a single constant current bias point for all laser diodes. The modulation current source can have a single temperature coefficient for all laser diodes. The laser driver can exclude, for example, any one of or combination of temperature compensation of the modulation or bias current sources, external programming of the modulation or bias current sources, power control based on output of the laser diode, and/or control based on feedback received from a monitor device or other sensor within the cables.

A fuel level sensor for sensing and monitoring the level of remaining fluid in a container such as a fuel tank for a motorized vehicle is disclosed. The fuel level sensor incorporates an improved float and pivot arm member attached to a hub that rotates about a pivot base. The conventional resistor card technology, commonly found in automotive applications for translating the position of the float into an electrical signal, is replaced by a more reliable non-contact magnetic flux sensing circuit. The fuel level sensor incorporates a magnetic sensor and magnetic circuit in a commonly known and practiced rotational position sensor configuration for determining the angular position of a hub relative to its pivot base, where the hub is attached to a conventional float-arm member and the base remains stationary relative to the fuel container. The preferred embodiment includes a magnetic flux sensor positioned between two movable magnets. The magnetic flux sensing element is a Hall effect integrated circuit, magnetoresistor, magnetodiode, magnetotransistor, or similar magnetic flux sensing element with associated electronic circuitry having adjustable or programmable features including ratiometry, gain, offset voltage, temperature coefficient, and output signal range limiting. Critical electronic components are hermetically sealed making the fuel level sensor fully submersible in fuel for long term fuel exposure.

A bandgap reference voltage generating circuit includes a proportional to absolute temperature (PTAT) voltage generating means generating a PTAT voltage. A complementary to absolute temperature (CTAT) voltage generating means generates a CTAT voltage. A temperature coefficient determining means interconnects the PTAT voltage generating means and the CTAT voltage generating means.

A gain compensation device for adjusting gain of an amplifier over temperature is disclosed. The gain of the amplifier is controlled by signals on a gain control end of the amplifier. The gain compensation device comprises a temperature compensation generator, an adder, and a temperature sensor. The temperature compensation generator is for generating an additional gain parameter according to a reference temperature, a current temperature, and a temperature coefficient. The adder comprises a first input end, coupled to the temperature compensation generator for receiving the additional gain parameter, a second input end for receiving a default gain parameter, and an output end coupled to the gain control end of the amplifier for outputting sum of the additional gain parameter and the default gain parameter. The temperature sensor is for providing the current temperature.

The band-gap reference voltage (RV) source with low temperature coefficient (TC) includes PTAT current generation circuit, start circuit of RV, combiner circuit of RV, neutralization circuit of base current, mirror circuit of first current. The band-gap RV source with low TC also includes generation circuit of second order temperature compensation current, which is connected to the mirror circuit of first current, and the combiner circuit of RV. Through square relation between drain-source current and grid-source voltage drop of MOS tube, inputting PTAT current and band-gap RV generates second order compensation current. The second order compensation current is output to the combiner circuit of RV to generate second order compensation voltage to compensate second order TC of RV so as to produce RV with very low TC. The invention overcomes issue of TC on the high side in traditional band-gap RV. Using standard CMOS technique realizes band-gap RV with very low TC.