A key arrangement includes an activation element, a switch, a mechanical counterforce generating device, and a permanent magnet arrangement. The switch has at least a first state and a second state. The activation element has a basic state and an activation state and is configured to, in case of activation by a user, permit a movement from the basic state into the activation state, and in case of the movement into the activation state to permit a change in the state of the switch. The mechanical counterforce generating device is configured to generate, in case of an activation of the activation element, a first counterforce at least in certain areas. The permanent magnet arrangement is configured to generate, in case of activation of the activation element, a second counterforce at least in certain areas.

Disclosed is a dual-input circuit, adopting a contactor as a switching device, and being more suitable for medium and high-power applications. In addition, the adopted contactor is a single double-pole double-throw contactor with an interlocking function. In this way, the circuit is safe, simple, and easily controllable, and space utilization can be further improved. In addition, the adopted contactor further is of a magnetic attraction type, with lower power consumption for long-term work. In the present invention, either one of two inputs is set as a main input and the other is set to a backup input by default, so that the present invention can be more flexibly applied and is more applicable. To enable switching when both or only either one of the two inputs has an input voltage, the present invention further adopts a single dual-input auxiliary power supply to reduce a required space and further reduce costs.

A door latch device includes: a first position switch and a second position switch, each including a first contact hole, a second contact hole, and a common contact hole; a common pin configured to be electrically conducted to the common contact hole of the first position switch and the first contact hole of the second position switch by being inserted therein; a first signal pin configured to be electrically conducted to the first contact hole of the first position switch by being inserted therein; and a second signal pin configured to be electrically conducted to the common contact of the second position switch by being inserted therein, wherein the first position switch and the second position switch are configured to perform a switch operation at a same timing of an operation of a predetermined operation detection target.

A switch circuit includes a first circuit including a first switch and first output terminals, and a second circuit including a second switch and second output terminals. The first circuit and the second circuit are connected in series. The first circuit has a circuit configuration in which a combination of resistors in a signal path between the first output terminals of the first circuit differs depending on the electrical conduction state of the first switch. The second circuit has a circuit configuration in which a combination of resistors in a signal path between the second output terminals of the second circuit differs depending on the electrical conduction state of the second switch.

A circuit-breaker includes an electronic trip unit, which initiates an interruption or reduction of the current flow in a low-voltage circuit when current or current-time limits are exceeded in the low-voltage circuit. The electronic trip unit includes at least two processors that independently check whether current or current-time limits are being exceeded. A test signal is fed to the circuit-breaker via a first communication interface, which is fed to one of the two processors during operation so that a test of the circuit-breaker is carried out during operation, while at the same time an active protection is provided with regard to the exceeding of current or current-time limits.

Embodiments of negative pressure wound therapy systems and methods are disclosed. In one embodiment, a system includes a wound dressing, negative pressure source, switch, and control circuitry. The switch can include an actuator that toggles states of first and second pairs of contacts in response to a user input. The control circuitry can supply negative pressure with the negative pressure source when the state of the first pair of contacts is a first state and the state of the second pair of contacts is a second state, and the control circuitry can disable supply of negative pressure with the negative pressure source when the state of the first pair of contacts is not the first state or the state of the second pair of contacts is not the second state.

A switch circuit includes a first circuit including a first switch and first output terminals, and a second circuit including a second switch and second output terminals. The first circuit and the second circuit are connected in series. The first circuit has a circuit configuration in which a combination of resistors in a signal path between the first output terminals of the first circuit differs depending on the electrical conduction state of the first switch. The second circuit has a circuit configuration in which a combination of resistors in a signal path between the second output terminals of the second circuit differs depending on the electrical conduction state of the second switch.

A circuit-breaker includes an electronic trip unit, which initiates an interruption or reduction of the current flow in a low-voltage circuit when current or current-time limits are exceeded in the low-voltage circuit. The electronic trip unit includes at least two processors that independently check whether current or current-time limits are being exceeded. A test signal is fed to the circuit-breaker via a first communication interface, which is fed to one of the two processors during operation so that a test of the circuit-breaker is carried out during operation, while at the same time an active protection is provided with regard to the exceeding of current or current-time limits.

An electronic switch includes a rubber sheet that includes a first surface, a second surface opposite to the first surface, and a convex portion on the first surface. The convex portion of the rubber sheet includes a semispherical shape.

A circuit breaker includes a first electrical contact and a second electrical contact moveable between an open state and a closed state; an armature, wherein movement of the armature from a first position to a second position initiates the first electrical contact and the second electrical contact to move from the closed state to the open state; a first electromagnetic device configured to move the armature from the first position to the second position in response to being energized by a first signal; and a second electromagnetic device configured to move the armature from the first position to the second position in response to being energized by a second signal and in response to generation of the first signal and the first electrical contact and the second electrical contact still being in the closed state. Other circuit breakers and methods of operating circuit breakers are disclosed.