A sensor head of a test and measurement instrument can include an input configured to receive an input signal from a device under test (DUT), an optical voltage sensor having signal input electrodes and control electrodes or one set of electrodes, wherein the input is connected to the signal input electrodes, and a bias control unit connected to the control electrodes and configured to reduce an error signal or the input signal bias control signal are electrically combined and applied to a single set of electrodes.

A sensor head of a test and measurement instrument can include an input configured to receive an input signal from a device under test (DUT), an optical voltage sensor having signal input electrodes and control electrodes or one set of electrodes, wherein the input is connected to the signal input electrodes, and a bias control unit connected to the control electrodes and configured to reduce an error signal or the input signal bias control signal are electrically combined and applied to a single set of electrodes.

A voltage transient detector includes circuitry for transmitting electrical current through a light emitting diode and a fuse that is serially connected between the light emitting diode and a reference potential, such that the light emitting diode is illuminated when the fuse is not blown. The voltage transient detector also includes circuitry for transmitting a controlled amount of electrical current through the fuse in conjunction with an occurrence of a voltage transient at a voltage measurement location, where the voltage transient exceeds a set transient threshold voltage. The controlled amount of electrical current transmitted through the fuse causing the fuse to blow and the light emitting diode to turn off, thereby indicating occurrence of the voltage transient at the voltage measurement location.

A system and method are provided for compensating for thermal drift of a probe device. The method includes monitoring a first temperature of a laser source in a sensor head that receives output electrical signals from a DUT and outputs corresponding optical signals; monitoring a second temperature of a photoreceiver in a probe interface that converts the optical signals to electrical test signals to input to the test instrument; calculating a first value of a first bias voltage using the first temperature; applying the first value of the first bias voltage to the laser source to compensate for thermal drift when the first temperature is within a first predefined temperature range; calculating a second value of a second bias voltage for the photoreceiver using the second temperature; and applying the second value of the second bias voltage to the photoreceiver to compensate for thermal drift when the second temperature is within a second predefined temperature range.

A system and method are provided for compensating for thermal drift of a probe device. The method includes monitoring a first temperature of a laser source in a sensor head that receives output electrical signals from a DUT and outputs corresponding optical signals; monitoring a second temperature of a photoreceiver in a probe interface that converts the optical signals to electrical test signals to input to the test instrument; calculating a first value of a first bias voltage using the first temperature; applying the first value of the first bias voltage to the laser source to compensate for thermal drift when the first temperature is within a first predefined temperature range; calculating a second value of a second bias voltage for the photoreceiver using the second temperature; and applying the second value of the second bias voltage to the photoreceiver to compensate for thermal drift when the second temperature is within a second predefined temperature range.

A battery system includes a battery module having a plurality of assembled batteries. Battery monitoring circuits are provided to correspond to each of the assembled batteries of the battery module. A control circuit controls operation of the battery monitoring circuits. A first signal transmission path transmits signals that are input and output between the battery monitoring circuits and the control circuit. A first isolation element is connected to the control circuit, and a second isolation element is connected to the battery monitoring circuit. The first signal transmission path is isolated from the control circuit by the second isolation element. The electrical potential of the first signal transmission path is a floating potential in relation to the electrical potentials of the control circuit and battery monitoring circuits.

A battery system includes a battery module having a plurality of assembled batteries. Battery monitoring circuits are provided to correspond to each of the assembled batteries of the battery module. A control circuit controls operation of the battery monitoring circuits. A first signal transmission path transmits signals that are input and output between the battery monitoring circuits and the control circuit. A first isolation element is connected to the control circuit, and a second isolation element is connected to the battery monitoring circuit. The first signal transmission path is isolated from the control circuit by the second isolation element. The electrical potential of the first signal transmission path is a floating potential in relation to the electrical potentials of the control circuit and battery monitoring circuits.

An apparatus for detecting a defect of an electric power system according to one embodiment of the present disclosure includes a first state signal output unit for outputting a first state signal corresponding to a magnetic force generated at a periphery of a line, a second state signal output unit for outputting a second state signal based on a magnitude of a line current and an increase ratio thereof, and a determination unit for determining whether the electric power system is defective or not based on the first state signal and the second state signal.

Described herein are systems and methods for low-power voltage sensor circuits and current sensor circuits using an optically coupled isolator. In various embodiments, opto-couplers replace bulky transformers that are used in common designs. In embodiments, an optically coupled isolator is used as a power gate to reduce power consumption. Further power savings may be obtained by selecting appropriate phototransistors and adjustable bias resistors to set the forward current of a photodiode as small as functionally possible to reduce battery discharge while providing sufficient gain for the optical transistor. In certain embodiments, the bias voltage point may be chosen to be at the turn-on voltage of the photodiode. In embodiments, power consumption of the voltage and current sensors may be adjusted by adjusting the frequency of a power-gating control signal, which may be controlled by a microcontroller. Embodiments may be used to produce low-cost alternatives that provide small form factor, high measurement accuracy, reliability, and longevity.

Described herein are systems and methods for low-power voltage sensor circuits and current sensor circuits using an optically coupled isolator. In various embodiments, opto-couplers replace bulky transformers that are used in common designs. In embodiments, an optically coupled isolator is used as a power gate to reduce power consumption. Further power savings may be obtained by selecting appropriate phototransistors and adjustable bias resistors to set the forward current of a photodiode as small as functionally possible to reduce battery discharge while providing sufficient gain for the optical transistor. In certain embodiments, the bias voltage point may be chosen to be at the turn-on voltage of the photodiode. In embodiments, power consumption of the voltage and current sensors may be adjusted by adjusting the frequency of a power-gating control signal, which may be controlled by a microcontroller. Embodiments may be used to produce low-cost alternatives that provide small form factor, high measurement accuracy, reliability, and longevity.