A method for estimating resistances of a circuit having a plurality of resistances comprising a first resistance and a second resistance may include applying a first bias voltage across the circuit and measuring a first voltage at a common node between the first resistance and the second resistance in order to determine a mathematical relationship between the first resistance and the second resistance, applying a second bias voltage across the circuit and a third resistance in parallel with the circuit and measuring a second voltage at the common node between the first resistance and the second resistance in order to determine a mathematical relationship between the third resistance and at least one of the first resistance and the second resistance, and based on at least the measurement of the first voltage and the measurement of the second voltage, determining the first resistance and the second resistance as a function of the third resistance.

Disclosed is a measuring bridge arrangement containing: a measuring bridge comprising at least one first half bridge having a first measuring connection and a second half bridge having a second measuring connection; a reference voltage divider having at least one first and a second test connection; a differential amplifier having at least one first and a second amplifier input and at least one amplifier output, a voltage amplification, and having an output voltage working range. In the arrangement, the first amplifier input is wired to a first capacitor and the second amplifier input is wired to a second capacitor, and the amplifier inputs can be selectively connected to the measuring connections or to the test connections.

A method is described for determining the resistance temperature characteristic of a ceramic glow plug, wherein the glow plug is heated at a specified power, wherein before the heating it is first determined whether the glow plug is an aged glow plug, and then, if the glow plug has not been detected as an aged glow plug, the glow plug is heated at a first specified power and the resistance value thereby achieved is assigned to a temperature that is anticipated to be the final temperature when heating a factory-outlet glow plug at this first power, or if the glow plug has been detected as an aged glow plug, the glow plug is heated at a reduced power which is smaller than the first power, and the resistance value achieved thereby is assigned to the same temperature that is also anticipated when heating a factory-outlet glow plug at the first power.

A detecting device for detecting a usage state of a socket includes a carrier, a movable assembly and a conductivity detecting module. The carrier has a first plug hole and a second plug hole. The movable assembly is movably disposed in the carrier. The conductivity detecting module is disposed on the carrier. The movable assembly is moved for exposing the first plug hole and the second plug hole by an external pushing force, and a detecting signal of the socket in-use is generated by the conductivity detecting module according to movement of the movable assembly.

Apparatus and associated methods relate to sensing a physical parameter and verifying correct operation of a system used to sense the physical parameter. A sensing device includes four resistive elements configured in a Wheatstone bridge configuration is configured to sense the physical parameter. A biasing network selectively provides first and second biasing conditions to the sensing device. First and second output electrical signals are generated by the sensing device in response to the first and second biasing conditions, respectively, selectively provided to the sensing device. The first and second output electrical signals are each indicative of the parameter value of the physical parameter, but not necessarily equal to one another. A verification module verifies correct operation of the system based on a consistency determination of first and second output electrical signals.

A single-chip magnetic field sensor bridge, comprising a substrate, a reference arm, a sensing arm, shielding structures, and wire bond pads is disclosed. The reference arm and the sense arm respectively comprise at least two rows/columns of reference element strings and sense element strings formed by electrically connecting one or more identical magnetoresistive sensing elements. The reference element strings and the sense element strings are alternately arranged. The magnetoresistive sensing elements are AMR, GMR or TMR sensing elements. The reference element strings are provided with shielding structures thereon, and the sensing element strings are located in gaps between two adjacent shielding structures. The shielding structures are arrays of elongated strips composed of permalloy or another soft ferromagnetic material. The sensors can be implemented as one of three different bridge structures, called a quasi-bridge, a half-bridge, or a full-bridge. This single-chip magnetic field sensor bridge has the advantages of small size, low cost, high sensitivity, small offset, good linearity, and good temperature stability.

A Wheatstone bridge array comprising a tunneling magnetoresistive (TMR) sensor and a method for manufacturing is disclosed. The bottom lead for the TMR sensor has a very small surface roughness due to not only chemical mechanical planarization (CMP) but also due to forming the bottom lead from multiple layers. The multiple layers include at least a bottom first metal layer and a top second metal layer disposed on the first metal layer. The second metal layer generally has a lower surface roughness than the first metal layer. Additionally, the second metal layer has a slower polishing rate. Therefore, not only does the second metal layer reduce the surface roughness simply be being present, but the slower polishing rate enables the top second metal film to be polished to a very fine surface roughness of less than or equal to ˜2 Angstroms.

The present invention discloses an AC impedance measurement circuit with a calibration function, which is characterized in that only one calibration impedance is needed, associated with a switch circuit. Based on the measurement results of the two calibration modes, an equivalent impedance of the switch circuit, circuit gain and phase offset can be calculated. Based on the above results, the equivalent impedance of the internal circuit is deducted from the measurement result of the measurement mode to accurately calculate an AC conductance and a phase of the AC conductance for impedance to be measured. In addition, by adjusting a phase difference between an input sine wave signal and a sampling clock signal, impedance of the same phase and impedance of the quadrature phase can be obtained, respectively, and the AC impedance and phase angle of the impedance to be measured can be calculated.

In accordance with an embodiment, a sensor includes: a signal source with a first signal source terminal and a second signal source terminal; a bridge circuit connected to the first and second signal source terminals, the bridge circuit including: a first branch including: a first reference impedance element; and a first sensor impedance element configured to transduce a magnitude to be measured into a first impedance-related parameter; and a second branch including: a second reference impedance element; and a second sensor impedance element configured to transduce the magnitude to be measured into a second sensor impedance-related parameter.

The disclosed techniques provide a number of technical benefits by providing a bridge sensor DC error cancellation scheme. In one embodiment, a system includes a piezoresistive Wheatstone bridge, a number of switches, and a non-overlapping clock. The system can mitigate noise and other errors by subtraction of the two differential outputs of the system between a first phase and a second phase of a clock input controlling the switches. In some embodiments, the system can also include differential programmable gain amplifiers and a multi-bit analog-to-digital converter. By providing a bridge sensor DC error cancellation scheme for producing an analog output, a system can be used to generate a stable digital output of at the analog-to-digital converter.