A zero-power plasmonic microelectromechanical system (MEMS) device is capable of specifically sensing electromagnetic radiation and performing signal processing operations. Such devices are highly sensitive relays that consume no more than 10 nW of power, utilizing the energy in detected electromagnetic radiation to detect and discriminate a target without the need of any additional power source. The devices can continuously monitor an environment and wake up an electronic circuit upon detection of a specific trigger signature of electromagnetic radiation, such as vehicular exhaust, gunfire, an explosion, a fire, a human or animal, and a variety of sources of radiation from the ultraviolet to visible light, to infrared, to terahertz radiation.

Zero power wireless sensors, devices, and systems are used for crop water content monitoring. The sensors consume no power while monitoring for the presence of dry crop conditions. Infrared reflectance from plants is measured and when selected spectral conditions are met, a circuit is closed, activating an alarm, an RFID tag, or a radio transmitter. The deployed sensors consume no power while monitoring, reducing or eliminating the need to change batteries.

An electric power system such as, for example, a circuit, an electric appliance, an electric generator, and/or an energy storage system, can be coupled with a negative thermal expansion component. The negative thermal expansion component can be formed from a material having negative thermal expansion properties such that the negative thermal expansion component contracts in response to an increase in temperature. The contraction of the negative thermal expansion component can form a nonconductive gap that disrupts current flow through the electric power system. The disruption of the current flow can eliminate hazards associated with the electric power system overcharging, overheating, and/or developing an internal short circuit.

An electric power system such as, for example, a circuit, an electric appliance, an electric generator, and/or an energy storage system, can be coupled with a negative thermal expansion component. The negative thermal expansion component can be formed from a material having negative thermal expansion properties such that the negative thermal expansion component contracts in response to an increase in temperature. The contraction of the negative thermal expansion component can form a nonconductive gap that disrupts current flow through the electric power system. The disruption of the current flow can eliminate hazards associated with the electric power system overcharging, overheating, and/or developing an internal short circuit.

Switches, breakers that incorporate a phase change material are disclosed, as well as electrical devices including the same. A switch includes a first conductor, a second conductor spaced a distance from the first conductor such that the second conductor does not contact the first conductor, and a switching device electrically coupled to the first conductor, the switching device having a phase change material that, when heated, expands to electrically contact the second conductor.

One embodiment of the invention includes a phase-change material switch. The switch includes a first terminal that receives an input signal and a second terminal. The switch includes an actuation portion that receives a control signal in one of a first state to emit a first heat profile and a second state to emit a second heat profile. The switch further includes a switch portion comprising a phase-change material arranged as a plurality of longitudinal strips that each interconnect the first terminal and the second terminal and that are each in proximity with the actuation portion. The phase-change material can be selectable between a conducting state in response to the first heat profile to conduct an input signal from the first terminal to the second terminal and a blocking state in response to the second heat profile to block the input signal from the first terminal to the second terminal.

One embodiment of the invention includes a phase-change material switch. The switch includes a first terminal that receives an input signal and a second terminal. The switch includes an actuation portion that receives a control signal in one of a first state to emit a first heat profile and a second state to emit a second heat profile. The switch further includes a switch portion comprising a phase-change material arranged as a plurality of longitudinal strips that each interconnect the first terminal and the second terminal and that are each in proximity with the actuation portion. The phase-change material can be selectable between a conducting state in response to the first heat profile to conduct an input signal from the first terminal to the second terminal and a blocking state in response to the second heat profile to block the input signal from the first terminal to the second terminal.

The present invention provides a relay with a shape memory alloy (SMA) wire driven mechanism. Conventional mechanical relays rely on electromagnetic principle to operate. Hence, magnetic fields of electromagnetic relays often interfere with magnetic fields of other electrical components, thus resulting in the components physically interfering with each other. The present invention utilizes the shape memory characteristics of a SMA wire to achieve the purpose of changing the operation of the relay. Specifically, when a SMA wire is heated, it restores to its original shape or original length. Comparing to conventional mechanical relays, the relay provided by the present invention does not magnetically interfere with other electrical components, and thus is able to function effectively. In addition, because the relay of the present invention does not require iron cores or coils, available space therein is increased and may be used to accommodate control circuits with various functions.

The present invention provides a relay with a shape memory alloy (SMA) wire driven mechanism. Conventional mechanical relays rely on electromagnetic principle to operate. Hence, magnetic fields of electromagnetic relays often interfere with magnetic fields of other electrical components, thus resulting in the components physically interfering with each other. The present invention utilizes the shape memory characteristics of a SMA wire to achieve the purpose of changing the operation of the relay. Specifically, when a SMA wire is heated, it restores to its original shape or original length. Comparing to conventional mechanical relays, the relay provided by the present invention does not magnetically interfere with other electrical components, and thus is able to function effectively. In addition, because the relay of the present invention does not require iron cores or coils, available space therein is increased and may be used to accommodate control circuits with various functions.

A surge protective device (SPD) module includes a module housing, first and second module electrical terminals mounted on the module housing, a gas discharge tube (GDT) mounted in the module housing, and a fail-safe mechanism mounted in the module housing. The GDT includes a first GDT terminal electrically connected to the first module electrical terminal and a second GDT terminal electrically connected to the second module electrical terminal. The fail-safe mechanism includes: an electrically conductive shorting bar positioned in a ready position and repositionable to a shorting position; a biasing member applying a biasing load to the shorting bar to direct the shorting bar from the ready position to the shorting position; and a meltable member. The meltable member maintains the shorting bar in the ready position and melts in response to a prescribed temperature to permit the shorting bar to transition from the ready position to the shorting position under the biasing load of the biasing member. In the shorting position, the shorting bar forms an electrical short circuit between the first and second GDT terminals to bypass the GDT.