The invention is related to a monitoring and protection device of power distribution transformers on the low voltage side. Said device monitors in a permanent manner the functioning of the transformer and provides a record of all the information in case of a fault. Additionally, the invention device provides the protection of the transformer in case of a fault, allowing a partial impact on the service and preventing peak currents that may reduce the useful life of the transformer. The device has a remote communication module that allows the transmission of the recorded data, a control module that may be activated remotely and a visual alert module that reduces the risk in the handling of the device.

A system including a vehicle having a motive electrical power path, a power distribution unit comprising a current protection circuit disposed in the motive electrical power path, the current protection circuit comprising a thermal fuse and a contactor in a series arrangement with the thermal fuse. The system further including a current source circuit electrically coupled to the thermal fuse and structured to inject a current across the thermal fuse, a hardware filter electrically coupled to the thermal fuse, the hardware filter comprising a cutoff frequency determined in response to an injection frequency of the current source circuit, and sa voltage determination circuit electrically coupled to the thermal fuse and structured to determine an injected voltage amount in response to the filtered injected current.

A circuit breaker includes a circuit breaker housing, an air-gap switch disposed within the housing, and a first visual indicator configured to provide an indication of an open state and a closed state of the air-gap switch. The first visual indicator includes a first window that is formed as part of the circuit breaker housing, and first and second indicator elements disposed within the circuit breaker housing. The first indicator element is configured to move into position behind the first window as the air-gap switch is placed into the open state and thereby provide a visual indication of the open state of the air-gap switch. The second indicator element is configured to move into position behind the first window as the air-gap switch is placed into the closed state and thereby provide a visual indication of the closed state of the air-gap switch.

An overcurrent protection circuit includes a current control part configured to control conductance of a transistor so as to limit an output current flowing when the transistor is turned on to a predetermined upper limit or less, and a duty control part configured to forcibly turning on/off the transistor at a predetermined duty ratio when a temperature protection circuit detects a temperature abnormality in a state where the current control part limits the output current.

A direct-current voltage supply circuit includes a first field effect transistor in a power line, a voltage divider including a first fixed resistor and a positive temperature coefficient thermistor between the power line and a ground line, a thyristor connected at an anode thereof to the power line, with a second field effect transistor interposed therebetween, connected at a gate thereof to a node in the voltage divider, and connected at a cathode thereof to the ground line, with a second fixed resistor interposed therebetween, and a third fixed resistor connected in parallel with the thyristor and the second field effect transistor. If abnormal heating increases the resistance of the positive temperature coefficient thermistor, the first field effect transistor is turned off and the supply of direct-current voltage is stopped.

A circuit for a smart semiconductor switch includes an electronic switch electrically coupled between an output node and a supply node. An overcurrent protective circuit is configured to generate an overcurrent signal in response to a load current flowing through the electronic switch exceeding a first overcurrent threshold, and to cause the electronic switch to be tripped. A control circuit is configured to switch the electronic switch on and off based on an input signal in a first mode, and to drive a load connected to the output node by repeatedly switching the electronic switch on and off in a second mode, and to prevent the electronic switch from being permanently tripped by the overcurrent protective circuit.

A short circuit protection circuit may comprise a first configuration channel line extending from a first connector, a first resistor connected to the first configuration channel line; a voltage divider connected to a junction point on the first configuration channel line, the voltage divider comprising a second resistor and a thermistor, and a field effect transistor (FET) comprising a source, gate, and drain. The thermistor may be connected to a ground line. The drain of the FET may be connected to the first resistor, the source of the FET may be connected to the ground line, and the gate of the FET may be connected to a second junction point between the second resistor and thermistor of the voltage divider.

A personal electronic device can include a main printed circuit board having disposed thereon a processing unit, one or more auxiliary circuits coupled to the main printed circuit board by one or more corresponding flexible printed circuits and one or more temperature sensors disposed on one of the flexible printed circuits. A processing unit of the portable electronic device can be configured to monitor the one or more temperature sensors, provide a warning in response to a monitored temperature exceeding a first threshold, and to cause a shutdown of at least a portion of the personal electronic device in response to the monitored temperature exceeding a second threshold. The temperature sensors can be negative temperature coefficient resistors.

A semiconductor unit includes a semiconductor device, a controller, and a resistor. The semiconductor device includes a transistor arranged between a positive electrode of a battery and an inverter circuit electrically connected to the battery. The controller is connected to a control terminal of the transistor and configured to control the transistor. The resistor arranged between the control terminal and the controller. The controller controls the transistor so that when a current flowing to the transistor is greater than or equal to a threshold value, the transistor is deactivated. The resistor has a resistance value that is greater than or equal to 100Ω.

A temperature fuse is ring-shaped and includes an insulation portion and a conductive portion arranged on an inner side and an outer side in a radial direction, and the conductive portion is formed of a thermal fuse element. An electrical junction box includes: a circuit board on which a switching element is mounted; a housing body for housing the circuit board; a conductive plate connected to the switching element, a first hole passing through the conductive plate; a terminal that is shaped as a plate and faces the conductive plate, a second hole passing through the terminal; the temperature fuse interposed between the conductive plate and the terminal in an axial direction, and a shaft-like insertion body for being inserted into the temperature fuse, the first hole, and the second hole.