Novel electrically-isolated high-voltage sensors are provided which have low power dissipation. The sensors are formed of a circuit comprising first and second portions separated by an electrical isolation boundary with the first portion used for high-voltage, and the second portion for low-voltage. While they are decoupled electrically, they are coupled both optically and magnetically. The first portion comprises an LED which generates an optical signal corresponding to a high-voltage signal across the electrical-isolation boundary. The second portion comprises a photodiode which receives the optical signal emitted from the LED and outputs a corresponding low-voltage electrical signal. A temperature-compensating LED biasing sub-circuit may span both portions and include a temperature sensor, a coupled inductor magnetically coupling the electrical isolation boundary, and a rectifier and filter, to provide a bias to the LED which biases the LED to operate in a substantially-linear manner irrespective of the ambient temperature.

An example test system includes a test head, and a device interface board (DIB) configured to connect to the test head. The DIB is for holding devices under test (DUTs). The DIB includes electrical conductors for transmitting electrical signals between the DUTs and the test head. Servers are programmed to function as test instruments. The servers are external to, and remote from, the test head and are configured to communicate signals over fiber optic cables with the test head. The signals include serial signals.

According to one aspect, an integrated circuit includes: an electronic module configured to generate a voltage at an output, and an electronic control circuit coupled to an output of the electronic module, the electronic control circuit comprising an emissive electronic component. The electronic control circuit is configured to cause the emissive electronic component to emit light radiation as a function of a value of the voltage at the output of the electronic module relative to a value of an operating voltage of the electronic module, and the operating voltage is specific thereto during normal operation of this electronic module. The light radiation emitted by the emissive electronic component is configured to diffuse to an outer face of the integrated circuit.

According to one aspect, an integrated circuit includes: an electronic module configured to generate a voltage at an output, and an electronic control circuit coupled to an output of the electronic module, the electronic control circuit comprising an emissive electronic component. The electronic control circuit is configured to cause the emissive electronic component to emit light radiation as a function of a value of the voltage at the output of the electronic module relative to a value of an operating voltage of the electronic module, and the operating voltage is specific thereto during normal operation of this electronic module. The light radiation emitted by the emissive electronic component is configured to diffuse to an outer face of the integrated circuit.

The present disclosure discloses a zero-crossing detection circuit, including: a zero-crossing judgment module, having a first end and a second end, wherein the first end is connected to a power supply and the second end is grounded; a photoelectric coupler, connected to the zero-crossing judgment module; an optocoupler driving module, connected to the photoelectric coupler; and an energy storage capacitor, wherein the energy storage capacitor is configured to provide excitation power for the photoelectric coupler and the optocoupler driving module.

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.

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 state detection apparatus includes a communication circuit that transmits information to an external apparatus, a control circuit that operates the communication circuit at a first timing, a battery that supplies electric power to the communication and control circuits, and a first explosion-proof barrier connected between a contact circuit and the control circuit. The control circuit applies a test signal, generated based on voltage from the battery, to the contact circuit at a second timing arriving at shorter intervals than the first timing, acquires a detection signal indicating current flow in the contact circuit due to test signal application, and regardless of the first timing, operates the communication circuit when the detection signal is acquired to transmit to the external apparatus that the state of a device connected to the contact circuit is abnormal.

A state detection apparatus includes a communication circuit that transmits information to an external apparatus, a control circuit that operates the communication circuit at a first timing, a battery that supplies electric power to the communication and control circuits, and a first explosion-proof barrier connected between a contact circuit and the control circuit. The control circuit applies a test signal, generated based on voltage from the battery, to the contact circuit at a second timing arriving at shorter intervals than the first timing, acquires a detection signal indicating current flow in the contact circuit due to test signal application, and regardless of the first timing, operates the communication circuit when the detection signal is acquired to transmit to the external apparatus that the state of a device connected to the contact circuit is abnormal.