Provided are a single-chip differential free layer push-pull magnetic field sensor bridge and preparation method, the magnetic field sensor bridge comprising: a substrate, a staggered soft magnetic flux concentrator array, and a GMR spin valve or a TMR magnetoresistance sensing unit array having a magnetic sensing axis in an X-direction on the substrate. A soft magnetic flux concentrator comprises sides parallel to an X-axis and a Y-axis, and four corners sequentially labeled as A, B, C and D clockwise from an upper left position. Magnetoresistive sensing units are located at gaps between the soft magnetic flux concentrators. Additionally, the magnetoresistive sensing units corresponding to the A and C corner positions and B and D corner positions of the soft flux concentrators are defined as push magnetoresistive sensing units and pull magnetoresistive sensing units, respectively. The push magnetoresistive sensing units are electrically interconnected into one or more push arms, and the pull magnetoresistive sensing units are electrically interconnected into one or more pull arms. The push arms and the pull arms are electrically interconnected to form a push-pull sensor bridge. The present invention has low power consumption, high magnetic field sensitivity, and can measure a magnetic field in the Y-direction.

Provided are a single-chip differential free layer push-pull magnetic field sensor bridge and preparation method, the magnetic field sensor bridge comprising: a substrate, a staggered soft magnetic flux concentrator array, and a GMR spin valve or a TMR magnetoresistance sensing unit array having a magnetic sensing axis in an X-direction on the substrate. A soft magnetic flux concentrator comprises sides parallel to an X-axis and a Y-axis, and four corners sequentially labeled as A, B, C and D clockwise from an upper left position. Magnetoresistive sensing units are located at gaps between the soft magnetic flux concentrators. Additionally, the magnetoresistive sensing units corresponding to the A and C corner positions and B and D corner positions of the soft flux concentrators are defined as push magnetoresistive sensing units and pull magnetoresistive sensing units, respectively. The push magnetoresistive sensing units are electrically interconnected into one or more push arms, and the pull magnetoresistive sensing units are electrically interconnected into one or more pull arms. The push arms and the pull arms are electrically interconnected to form a push-pull sensor bridge. The present invention has low power consumption, high magnetic field sensitivity, and can measure a magnetic field in the Y-direction.

A vibrational energy harvesting device is disclosed, which comprises first and second assemblies mounted on a base at a distance one from the other. The first assembly comprises vibrational means adapted to stretch under a straining force, whereby the device exhibits monostable quartic nonlinearity. The first and second assemblies comprise respective magnetised means in opposite polarity to one another, so that the second assembly exerts a repulsive magnetic force upon the vibrational means, whereby the device exhibits bistability. Both the monostable quartic and bistable nonlinearities can be independently controlled. A method of harvesting energy with the vibrational energy harvesting device is also disclosed.

A vibrational energy harvesting device is disclosed, which comprises first and second assemblies mounted on a base at a distance one from the other. The first assembly comprises vibrational means adapted to stretch under a straining force, whereby the device exhibits monostable quartic nonlinearity. The first and second assemblies comprise respective magnetised means in opposite polarity to one another, so that the second assembly exerts a repulsive magnetic force upon the vibrational means, whereby the device exhibits bistability. Both the monostable quartic and bistable nonlinearities can be independently controlled. A method of harvesting energy with the vibrational energy harvesting device is also disclosed.

Inputting an input resistance to an operational amplifier. Detecting whether a number of fans are in operation based on the input resistance to the operational amplifier by driving a number of resistors connected in series in a fan circuit associated with the number of fans.

Inputting an input resistance to an operational amplifier. Detecting whether a number of fans are in operation based on the input resistance to the operational amplifier by driving a number of resistors connected in series in a fan circuit associated with the number of fans.

The double layer capacitance of a working electrode of a sensor may be measured with minimal disruption to the sensor equilibrium by open circuiting the working electrode and measuring the voltage drift on a periodic, or as-needed, basis. The values of the double layer capacitance may be monitored over time to determine, e.g., sensor age and condition.

The double layer capacitance of a working electrode of a sensor may be measured with minimal disruption to the sensor equilibrium by open circuiting the working electrode and measuring the voltage drift on a periodic, or as-needed, basis. The values of the double layer capacitance may be monitored over time to determine, e.g., sensor age and condition.

A method for monitoring degradation of a flashlamp including triggering the flashlamp to produce a light pulse, monitoring at least one parameter as a function of time to obtain a pulse waveform of the light pulse, comparing the pulse waveform to at least one reference pulse waveform to determine a difference therebetween, and flagging an end-of-lamp-life condition when the difference exceeds a predetermined threshold.

A method for monitoring degradation of a flashlamp including triggering the flashlamp to produce a light pulse, monitoring at least one parameter as a function of time to obtain a pulse waveform of the light pulse, comparing the pulse waveform to at least one reference pulse waveform to determine a difference therebetween, and flagging an end-of-lamp-life condition when the difference exceeds a predetermined threshold.