An electrical receptacle contains contacts, at least one contact for electrical connection to a hot power line and at least one contact for a neutral power line. A controlled switch, such as a TRIAC, is connected in series relationship between the contact and the hot power line. One or more sensors are provided which detect signals of the hot power line and/or the neutral power line. The processor provides activation or deactivation control to the controlled switch in response to the detected signals that are indicative of conditions relative to the first and second contacts.

A DC voltage source, for example an AC/DC converter, has an output producing a controllable DC voltage for a DC charging station to charge the battery of an electric vehicle. A voltage balancing unit is connected between the output of the converter and the output terminal of the DC charging station. The voltage balancing unit has a controllable switch by which the connection between voltage source or converter and battery can be made or broken as desired. The switch is controlled as a function of the voltage on the input and output side of the voltage balancing unit to the effect that the switch breaks the connection before and while the battery is being connected to the DC output terminal, and makes a connection only when the voltage on the input side of the voltage balancing unit corresponds substantially to the voltage on the output side of the voltage balancing unit.

An external power supply system for an aircraft includes a power receptacle configured to connect to an external power source to provide external power, a power switch operative to switch between a battery power source and the external power source, and a voltage check system configured to prevent at least one of under-voltage or over-voltage of an aircraft electrical system. The voltage check system includes a voltage relay sensor configured to determine if the external power is within a suitable voltage range and a check switch operatively connected to the voltage relay sensor, wherein if the external power is within a suitable voltage range, the voltage relay sensor activates the check switch to allow external power to the aircraft electrical system, and wherein if the external power is outside the suitable voltage range, then the voltage relay sensor does not allow power to the aircraft electrical system.

An apparatus for providing protection to an electric circuit includes a P-channel MOSFET; a freewheeling diode coupled to a drain of the P-channel MOSFET and coupled to a load; and a charge pump coupled to a gate of the P-channel MOSEFT. In a normal operating mode, the charge pump receives a voltage from a voltage regulator, and is configured to multiply and reverses the polarity of the voltage to supply to the gate of the MOSFET. In a reverse battery operating mode, the charge pump receives no voltage from the voltage regulator to supply to the gate of the MOSFET causing the MOSFET to deactivate such that when the MOSFET deactivates, current is prevented from flowing through the freewheeling diode to protect the freewheeling diode.

A load driving method includes bringing an output transistor disposed between a first power supply line and an output terminal connected to a load into a conduction state by a protection transistor provided between a gate of the output transistor and a second power supply line when a polarity of a power supply coupled between the first power supply line and the second power supply lines is reversed, and forming a conductive path between the second power supply line and a back gate of the protection transistor via a transistor by a back gate control circuit when the polarity of the power supply is normal, the back gate control circuit including the transistor, a gate of the transistor being coupled to the first power supply line directly via a connection node located in a connecting line that couples the first power supply line and the output transistor, the transistor being coupled between the second power supply line and the back gate of the protection transistor.

A load driving device includes a lockout circuit unit (70) that, when a battery is connected in reverse to a drive circuit unit (10), autonomously decreases a gate-source voltage of an anti-reverse connection relay (41, 42) down to a voltage that interrupts conduction between a source electrode and a drain electrode.

An apparatus for monitoring an electrical apparatus, the load monitoring apparatus comprising a controller which is configured to capture and process voltage and current data of an electrical apparatus, which is electrically connected with a power supply, to obtain electrical parameters of the electrical apparatus, to store the electrical parameters as measured electrical parameters, to compare the measured electrical parameters with a set of pre-stored electrical parameters, to determine whether the measured electrical parameters match with the stored electrical parameters, and to operate a power switch to turn off power supply to the electrical parameters if the measured electrical parameters do not match with the stored electrical parameters.

A polarity reversal protection circuit includes a MOSFET and a turn-off circuit, which turns off the MOSFET in the case of a polarity reversal. The turn-off circuit includes a detector for detecting the case in which the voltage at the source terminal of the MOSFET undershoots the voltage at the drain terminal of said MOSFET. Furthermore, it includes a quick-break switch for turning off the MOSFET in the event of detected voltage undershooting, a comparator for comparing the voltages present at source terminal and drain terminal of the MOSFET after detected voltage undershooting, wherein the output of the comparator is connected to the gate terminal of the MOSFET, a boost converter, a buck converter and a charge pump for voltage supply, and a switch for switching off the comparator.

The invention relates to a restart protection device (1) for a battery-powered electric hand tool (2), comprising—a control capacitor (C.sub.CTRL) having a cathode and an anode, wherein the cathode can be connected to an earth connection (10) of the electric hand tool (2) and the anode can be connected via a battery pack interface (4) of the electric hand tool (2) to a connector wire (6) of a battery pack (3) of the electric hand tool (2); —a controllable discharge circuit (14) designed for discharging the control capacitor (C.sub.CTRL), wherein a control input of the discharge circuit (14) can be connected via the battery pack interface (4) to a signal line (9) of the battery pack (3); —a measuring device (15) designed to determine a charge state of the control capacitor (C.sub.CTRL); and—a control device (13) connected to the measuring device (15), which control device is configured to inhibit start-up of the electric hand tool (2) if the charge state of the control capacitor (C.sub.CTRL) determined by means of the measuring device (15) is below a specified threshold value and an operating switch (12) on the electric hand tool (2) is pressed at the same time.

A soft starter includes a plurality of live phases, wherein a semiconductor switching element and an electromechanical switch parallel-connected thereto are arranged in each phase. In the soft starter, on a load-facing side of the semiconductor switching elements and of the electromechanical switches, the plurality of phases are connected in a circuit forming a star point. The star point circuit includes at least one passive component and is configured for detecting a reduced voltage drop in a defective state of a semiconductor switching element and/or of an electromechanical switch.