TWI413145B - Pressure controlling switch and method applied the same and alert system using the same - Google Patents

Abstract

The disclosure relates to a pressure controlling switch. The temperature controlling switch includes a bistable resistance element. The bistable resistance element includes a polymer matrix and a plurality of metallic particles dispersed in the polymer matrix. The bistable resistance element has a high resistance state and a low resistance state. For the low resistance state, a plurality of metallic filaments will be formed on surfaces of the metallic particles and form a conductive path in the bistable resistance element. For the high resistance state, most of the metallic filaments will be broken down, whereby the conductive path will be broken down. A trigger signal of the low resistance state can be an incentive electrical filed. A trigger signal of the high resistance state can be a temperature difference signal. The disclosure also relates to a method applied the same and an alert system using the same.

Description

Voltage control switch, application method thereof and alarm system using the same

The invention relates to a pressure control switch, a method of applying the pressure control switch and an alarm system using the same.

For some situations where anti-theft or anti-shock is required, such as the vault, test machine, etc., a pressure-controlled switch is needed to monitor the change of the working pressure in this occasion. The pressure control switch can not only sense the working pressure, but also maintain the pressure control switch in a fixed working state when the change of the working pressure is greater than or less than a set value according to the change of the working pressure. An alarm system connected to the voltage-controlled switch can be kept in an alarm state even if the change in the working pressure in this case is eliminated.

In order to enable the voltage control switch to maintain a fixed working state when the pressure change is monitored, the voltage control switch includes not only a pressure sensor for sensing the working pressure, but also an integrated chip or circuit with logic operation capability. The integrated chip or circuit determines whether the change in the working pressure is greater than or equal to the set value according to the pressure signal sensed by the pressure sensor. When the change in the operating pressure is greater than or less than the set value, the integrated wafer issues an operational command and maintains the voltage controlled switch in a fixed operational state.

As can be seen from the above description, in order for the voltage control switch to monitor the working pressure change to operate in a fixed working state, the voltage control switch must include a complex logic operation element, such as the above integrated chip, so that the voltage control The switch includes more devices and the structure is more complicated.

In view of this, it is necessary to provide a voltage control switch having a simple structure, a method of applying the voltage control switch, and an alarm system using the voltage control switch.

A voltage controlled switch comprising a bistable resistive element comprising a polymer carrier and a plurality of metal particles dispersed in the polymer carrier. The bistable resistive element has two operating states of a low resistance state and a high resistance state. In the low resistance state, the surface of the plurality of metal particles is formed with a metal conductive wire, and the plurality of metal particles form a conductive path through the metal conductive wire. In the high resistance state, the metal conductive wire on the surface of the plurality of metal particles is broken to break the conductive path. The trigger signal of the low resistance state is an excitation electric field. The high-impedance trigger signal is a differential pressure signal, and the differential pressure signal directly acts on the bistable state when the conductive path is formed directly on the initial pressure of the bistable resistive element and the conductive path is disconnected. One of the resistive elements triggers an absolute difference in pressure.

A voltage controlled switch comprising a bistable resistive element comprising a polymer carrier and a plurality of metal particles dispersed in the polymer carrier. An excitation electric field generating unit is configured to generate an excitation electric field to form the plurality of metal particles to form a conductive path and to memorize an initial pressure. A differential pressure signal generating unit is configured to generate a differential pressure signal equal to or greater than a minimum differential pressure to disconnect the conductive path.

A voltage controlled switch includes a bistable resistive element, an excitation electric field generating unit that emits an electric field, and a differential pressure generating unit that emits a differential pressure signal. The bistable resistive element comprises a polymer carrier and a plurality of metal particles dispersed in the polymer carrier. The excitation electric field acts on the bistable resistive element to form the conductive metal path to form a conductive path and the bistable resistive element memorizes an initial pressure; the differential pressure signal generating unit is configured to generate a minimum differential pressure equal to or greater than a minimum The differential pressure signal causes the conductive path to open.

A method for applying a voltage controlled switch, comprising the steps of: providing a bistable resistive element comprising a polymer carrier and a plurality of metal particles dispersed in the polymer carrier; when the voltage control needs to be monitored When the working pressure of the environment in which the switch is placed changes, an exciting electric field is applied to the bistable resistive element at the initial pressure P1, so that the bistable resistive element is in a low resistance state; when the pressure of the bistable resistive element is When the variation exceeds the minimum differential pressure ΔP, the bistable resistance element changes from a low resistance state to a high resistance state and is maintained at a high resistance state.

An alarm system includes an alarm device and a voltage control switch. The voltage control switch is used to control the alarm device alarm. The voltage control switch comprises a bistable resistance element, an excitation electric field generating unit and a differential pressure signal generating unit. The bistable resistive element comprises a polymer carrier and a plurality of metal particles dispersed in the polymer carrier. The excitation electric field generating unit is configured to apply an excitation electric field to operate the bistable resistance element in a low resistance state. The differential pressure signal generating unit is configured to generate a differential pressure signal to operate the bistable resistive element in a high resistance state.

Compared with the prior art, the bistable resistive element in the voltage control switch is switched between the low impedance state and the high impedance state by the excitation electric field and the differential pressure signal, and automatically switches after sensing the differential pressure signal. To high resistance. Therefore, the voltage control switch does not need a complicated logic operation component, and only needs a bistable resistance component to monitor the change of the working pressure of the environment in which the voltage control switch is located, and can monitor the change of the working pressure. It is kept in a fixed working state, such as a high resistance state, so that the voltage control switch has a simple structure. Further, the bistable resistive element operates in a low resistance state under the excitation electric field, and can be used to monitor the differential pressure signal again.

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 1 , an embodiment of the present invention provides a voltage control switch 100 including a bistable resistive element 10 , an excitation electric field generating unit 20 , and a differential pressure signal generating unit 30 .

Referring to FIGS. 2 to 4, the bistable resistive element 10 is a composite material comprising a plurality of metal particles 11 and a polymer carrier 12 dispersed in the polymer carrier 12. The bistable resistive element 10 has two operating states of a low resistance state and a high resistance state. In the low resistance state, the surface of the plurality of metal particles 11 is formed with a metal conductive wire 13 through which the plurality of metal particles 11 form a conductive path. In the high resistance state, the metal conductive wire 13 on the surface of the plurality of metal particles 11 is broken to break the conductive path. The polymer carrier 12 is an insulating material having a significant deformation in a stressed state, and the polymer carrier 12 is used to support the metal particles 11 and to cause significant deformation or volume change when pressed or stretched. In the present embodiment, the metal particles 11 are nickel particles having a particle diameter of about 1 μm to 6 μm, and the volume ratio of the nickel particles in the bistable resistive element 10 is between 9% and 11%; The carrier 12 is a ruthenium rubber (about 0.01 to 0.1) having a small elastic modulus for supporting the metal particles 11. Specifically, the ratio of the elastic modulus of the nickel particles to the polymer carrier 12 is greater than or equal to 2000. Dimethyl methoxide (PDMS: PolyDimethylsiloxane); the ratio of the resistance of the bistable resistive element 10 in the high resistance state to the resistance in the low resistance state is approximately between 10 ³ :1 and 10 ⁴ :1.

The excitation electric field generating unit 20 is configured to generate an excitation electric field, and the excitation electric field directly acts on the bistable resistance element 10 to operate the bistable resistance element 10 in a low resistance state, that is, the excitation electric field is the bistable resistance Element 10 operates on a low impedance trigger signal. Specifically, referring to FIG. 3, the plurality of metal particles 11 in the bistable resistive element 10 extend from the surface to excite the plurality of metal conductive wires 13 under the excitation of the excitation electric field, thereby passing between the adjacent two metal particles 11. The metal conductive wires are connected to each other such that the number of metal particles 11 electrically connected to each other is increased to form a conductive path, and the resistance of the bistable resistive element 10 is shifted, so that the bistable resistive element 10 operates at a low resistance. state. In the embodiment, the excitation electric field generating unit 20 is a pulse signal generating device, and the exciting electric field is a pulse electric field. The pulsed electric field has a width of between 1 millisecond and 10 seconds and an intensity of between 0.3 volts per millimeter to 3 volts per millimeter. The excitation field can be loaded into the bistable resistive element 10 by any means, such as placing the bistable resistive element 10 in an environment having the exciting electric field, such as a capacitor.

The differential pressure signal generating unit 30 is configured to generate a differential pressure signal to cause a pressure change of the bistable resistive element 10. The differential pressure signal is a pressure change that directly acts on the bistable resistive element 10. When the differential pressure signal exceeds a minimum differential pressure, that is, when the absolute value of the pressure change of the bistable resistive element 10 is greater than a predetermined value, the bistable resistive element 10 operates in a high impedance state, that is, the differential pressure signal The trigger signal for operating the bistable resistive element 10 in a high impedance state. Defining the voltage of the bistable resistive element 10 when the conductive path is formed is an initial pressure, and the differential pressure generating unit 30 generates a differential pressure signal, so that the bistable resistive element 10 operates in a high impedance state, the bistable The state resistance element 10 is a trigger pressure, and the differential pressure signal is an absolute difference between the trigger pressure and the initial pressure. For example, when the conductive path is formed, the initial pressure is 20 Pa, and after the differential pressure signal generating unit 30 acts on the bistable resistive element 10, the bistable resistive element 10 is operated in a high resistance state, and the trigger pressure is 15 Pa, the pressure difference signal is 5 Pa. That is, the differential pressure signal is a pressure change intensity or a pressure change value of the environment in which the bistable resistive element 10 is placed when the conductive path is formed and broken. In addition, depending on the pressure of the bistable resistive element 10 when forming the conductive path, the bistable resistive element 10 may have a different initial pressure, that is, the initial pressure when the bistable resistive element 10 forms a conductive path is Can be changed. When the bistable resistive element 10 is triggered by the excitation electric field to form a conductive path at different pressures, the bistable resistive element 10 can have an initial pressure of unequal values, and can have an initial value of a complex number. pressure. That is, the value of the initial pressure when the bistable resistive element 10 is switched between the high resistance state and the low resistance state is variable. For example, the bistable resistive element 10 has an initial pressure of 20 Pa when operating in a low resistance state for the first time and a trigger pressure of 15 Pa when switching to a high resistance state. At this time, if an exciting electric field is applied to the bistable resistive element 10 at 15 Pa to operate the bistable resistive element 10 in a low resistance state, the bistable resistive element 10 operates in a low resistance state for the second time. The initial pressure is 15 Pa. Therefore, the initial pressure is determined according to the pressure of the bistable resistive element 10 when the bistable resistive element 10 is operated in a low resistance state by applying an exciting electric field, and is changeable. In addition, the method of generating the differential pressure signal and the configuration of the differential pressure signal generating unit 30 employed therein are not limited as long as the pressure acting directly on the bistable resistive element 10 can be changed. For example, the differential pressure signal may be a change in ambient pressure in a space in which the bistable resistive element 10 is placed, such as a change in gas pressure in a reactor; a change in gas pressure caused by coughing or vibration. In addition, the differential pressure signal may also be a change in the tensile force or a change in pressure directly acting on the bistable resistive element 10.

In operation, the bistable resistive element 10 has a different minimum differential pressure at different initial pressures. When the bistable resistive element 10 receives an excitation electric field at an initial pressure, the plurality of metal particles 11 form a conductive path, and at this time, the bistable resistive element 10 operates in a low resistance state. At this time, the bistable resistive element 10 has a corresponding minimum differential pressure at the initial pressure. Referring to FIG. 4, when the bistable resistive element 10 receives a differential pressure signal greater than the minimum differential pressure, the bistable resistive element 10 undergoes a deformation or a significant volume change under the action of the differential pressure signal. The sliding of the molecular chain in the bistable resistive element 10 is caused to break the conductive path, and the bistable resistive element 10 is operated in a high resistance state. Specifically, since the elastic modulus of the polymer carrier 12 is much smaller than the elastic modulus of the metal particles 11, preferably, the ratio of the elastic modulus of the metal particles 11 to the elastic modulus of the polymer carrier 12 is 50 or more. . The polymer carrier 12 is deformed under the pressure difference signal to cause a relative slip between the plurality of metal particles 11 to change the distance between the metal particles 11, thereby breaking the plurality of metal conductive wires 13. Moreover, the effect of the differential pressure signal on the conductive path is irreversible, and even if the differential pressure signal is cancelled, or a different differential pressure signal is applied again, the conductive path is still in an open state, so that the bistable resistive element 10 still works in high resistance.

Please refer to FIG. 5 , which is a schematic diagram of a current variation curve when the bistable resistive element 10 is electrically connected to a power source in the embodiment. Specifically, the bistable resistive element 10 is a film-like structure and is naturally placed in an atmospheric environment. The power source is a pulse power source, and the width between adjacent two pulse excitation electric fields is 100 milliseconds, that is, every 100 milliseconds. The bistable resistive element 10 is given an excitation electric field. At the same time, a pulse pressure of greater than or equal to 0.3 N/m 2 is applied to a surface of the film structure every 500 msec, that is, a differential pressure signal is applied to the bistable resistive element 10 every 500 msec. As can be seen from FIG. 5, when the bistable resistive element 10 receives the pulse pressure, the resistance of the bistable resistive element 10 is greater than or equal to 10 ⁷ ohms, operating in a high resistance state; and when the pulse pressure disappears, the bistable resistance element 10 under the action of an electric field excitation pulse of approximately ¹⁰⁵ ohms resistance, is switched to the low resistance state and to remain.

The type and particle diameter of the metal particles 11 in the bistable resistive element 10, the volume ratio in the bistable resistive element 10, and the type of the polymer carrier 12, in addition to the materials and structures exemplified in the present embodiment. There are no special restrictions. As long as the metal particles 11 are satisfied under an excitation electric field, a conductive path can be formed, and the conductive path can be broken when the polymer carrier 12 is significantly deformed. Specifically, the metal particles 11 may also be gold, silver, tin, iron, copper or platinum, and the metal particles 11 may have a particle size ranging from 2 nm to 20 μm, and the metal particles 11 are in the bistable resistive element. The volume ratio in 10 can be 5% to 40%. The polymer carrier 12 may also be a series of other ruthenium rubbers other than polydimethyl siloxane; the polymer carrier 12 may also be a polymer such as polyethylene glycol or polypropylene; It can be polyester, epoxy resin series, anoxic glue series or acrylic glue series. The ratio of the resistance of the bistable resistive element 10 in the high resistance state to the resistance in the low resistance state is greater than 10 ² :1. Further, referring to FIG. 6, the voltage control switch 100 may further include two electrodes 40 distributed on opposite surfaces of the bistable resistive element 10, such as the bistable resistive element 10 being In the case of a film-like structure, the two electrodes 40 can sandwich the film-like structure to form a sandwich structure. The voltage control switch 100 can be electrically connected to an external circuit through the two electrodes, such as a control circuit or an alarm device. For ease of operation, the excitation electric field generating unit 20 can be electrically connected to the bistable resistance element 10 through the two electrodes 40. The material of the electrode 40 is not limited, and includes a metal, a conductive paste or a metallic carbon nanotube.

The bistable resistive element 10 of the voltage control switch 100 is switched between the low impedance state and the high impedance state by the excitation electric field and the differential pressure signal, and automatically switches to a high resistance state after sensing the differential pressure signal. . Therefore, the voltage control switch 100 does not need a complicated logic operation component, and only needs a bistable resistance component 10 to monitor the change of the working pressure of the environment in which the voltage control switch 100 is located, and can monitor the working pressure. The change is maintained in a fixed working state, such as a high resistance state, thereby making the voltage control switch 100 simple in structure. Further, the bistable resistive element 10 operates in a low resistance state under the excitation electric field, and can be used to monitor the differential pressure signal again.

Referring to FIG. 7, a method for applying the voltage control switch 100 includes the following steps.

In step S101, a bistable resistive element 10 is provided. The bistable resistive element 10 includes a polymer carrier 12 and a plurality of metal particles 11 dispersed in the polymer carrier 12.

Step S102, when it is required to monitor the working pressure change of the environment in which the voltage control switch 100 is located, an excitation electric field is applied to the bistable resistance element 10 at the initial pressure P1, so that the bistable resistance element 10 is at and remains low. Resistance state. The initial pressure P1 is the pressure of the bistable resistive element 10 when the exciting electric field is applied.

In step S103, when the pressure change of the bistable resistive element 10 exceeds the minimum differential pressure ΔP, the bistable resistive element 10 changes from a low resistance state to a high resistance state and is maintained in a high resistance state. That is, when the absolute difference │P2-P1 │ ≥ ΔP between the trigger pressure P2 of the bistable resistive element 10 and the pressure of the initial pressure P1, the operating state of the bistable resistive element 10 is changed and fixed. In high resistance state.

As can be seen from the above description, when the voltage control switch 100 is applied, an optimum working pressure can be determined first, for example, the pressure of the bistable resistive element 10 is 1.01 × 10 ⁵ Pa at a standard atmospheric pressure. The bistable resistive element 10 is electrically excited to operate in a low resistance state at the optimum operating pressure. At this time, the voltage control switch 100 can be used to monitor the working pressure change of the environment. However, when the working pressure rises or falls by more than ΔP, the bistable force is applied when the pressure applied to the bistable resistive element 10 increases or the weight of the object is directly applied to the bistable resistive element 10, such as external vibration. The pressure of the ohmic resistance element 10 is increased; when the bistable resistance element 10 is externally stretched or the external gas pressure is lowered, the pressure of the bistable resistance element 10 is reduced, and the bistable resistance element 10 is automatically switched to high. The resistance state until the excitation of the next excitation electric field.

FIG. 8 is an alarm system 200 for using the voltage control switch 100 provided by the embodiment of the present invention. The alarm system 200 further includes a power source 210 and an alarm device 220.

The power source 210 is electrically connected to the voltage control switch 100 and the alarm device 220 to form a loop. The power source 210 is configured to supply a voltage to the loop, and an electric field generated by the power source 210 in the bistable resistive element 10 does not trigger the bistable resistive element 10 to operate the bistable resistive element 10 in a high resistance state. .

The voltage control switch is used to control the alarm device 220 to alarm. Specifically, when the excitation electric field generating unit 20 generates an excitation electric field to operate the voltage control switch 100 in a low resistance state, the alarm device 220 is configured to monitor the differential pressure change of the differential pressure signal generating unit 30. When the differential pressure signal generating unit 30 generates a differential pressure signal to cause the voltage control switch 100 to operate in a high impedance state, the alarm device 220 sends an alarm signal. That is, the alarm device 220 sends an alarm signal only when the voltage control switch 100 memorizes the differential pressure signal until the voltage control switch 100 receives an excitation electric field.

The alarm device 220 and the voltage control switch 100 can be connected in series in the circuit or in parallel. In the embodiment, the alarm device 220 can be connected in series with the voltage control switch 100. When the voltage control switch 100 is operated in a high impedance state, the loop current is reduced, so that the alarm device 220 sends an alarm signal.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

100‧‧‧Voltage control switch

10‧‧‧Bistable resistance element

11‧‧‧ metal particles

12‧‧‧ Polymer carrier

13‧‧‧Metal conductive wire

20‧‧‧Excitation electric field generating unit

30‧‧‧ Differential pressure signal generating unit

40‧‧‧Electrode

200‧‧‧ alarm system

210‧‧‧Power supply

220‧‧‧ alarm device

FIG. 1 is a schematic structural diagram of a voltage control switch according to an embodiment of the present invention.

2 is a schematic structural view of a bistable resistance element in the voltage control switch of FIG. 1.

3 is a schematic view showing the structure of the bistable resistive element of FIG. 2 formed with a conductive path.

4 is a schematic view showing the structure of the bistable resistive element of FIG. 3 when the conductive path is broken.

FIG. 5 is a schematic diagram of a resistance change curve when a voltage control switch is externally connected to a power supply and simultaneously receives a plurality of differential pressure signals and a plurality of excitation electric field signals according to an embodiment of the present invention.

FIG. 6 is a schematic structural diagram of another voltage control switch provided by the implementation of the present invention without including a differential pressure generating device.

FIG. 7 is a schematic flow chart of applying a voltage control switch according to an embodiment of the present invention.

FIG. 8 is a schematic diagram of a connection of an alarm system with a voltage control switch according to an embodiment of the present invention.

10‧‧‧Bistable resistance element

11‧‧‧ metal particles

12‧‧‧ Polymer carrier

13‧‧‧Metal conductive wire

Claims (19)

A voltage controlled switch comprising a bistable resistive element, the bistable resistive element comprising a polymer carrier and a plurality of metal particles dispersed in the polymer carrier;
The bistable resistive element has two operating states: a low resistance state and a high resistance state;
In the low resistance state, the surface of the plurality of metal particles is formed with a metal conductive wire, and the plurality of metal particles form a conductive path through the metal conductive wire, and the trigger signal of the low resistance state is an excitation electric field;
In a high-resistance state, the metal conductive wire on the surface of the plurality of metal particles is broken to break the conductive path, and the high-impedance trigger signal is a differential pressure signal, and the differential pressure signal directly acts on the conductive path when the conductive path is formed. The initial pressure of one of the bistable resistive elements directly acts on the absolute difference of the trigger pressure of one of the bistable resistive elements when the conductive path is disconnected. The voltage-controlled switch of claim 1, wherein the excitation electric field is from 0.1 volts per centimeter to 100 volts per centimeter. The voltage control switch according to claim 1, wherein the initial pressure of the bistable resistive element when operating in a low resistance state corresponds to a minimum differential pressure, and the differential pressure signal is greater than or equal to the minimum differential pressure. The voltage-controlled switch according to claim 1, wherein the ratio of the resistance of the bistable resistance element in the high resistance state to the resistance in the low resistance state is greater than or equal to 10 ² . The pressure-controlled switch according to claim 1, wherein a ratio of an elastic modulus of the metal particles to an elastic modulus of the polymer carrier is 50 or more. The pressure-controlled switch according to claim 1, wherein in the high-resistance state, the polymer carrier is deformed by the differential pressure signal to cause a relative slip between the plurality of metal particles, thereby The conductive path is broken. The pressure-controlled switch according to claim 1, wherein the metal particles have a volume fraction of 5% to 40% in the bistable resistance element. The pressure-controlled switch of claim 1, wherein the metal particles have a particle size ranging from 2 nm to 20 μm. The pressure-controlled switch according to claim 1, wherein the metal particles are nickel particles having a particle diameter of between 1 μm and 6 μm, and the polymer carrier is a ruthenium rubber, and the nickel particles are in the bistable state. The volume fraction in the resistive element is between 8% and 12%. The voltage control switch according to claim 1, wherein when the bistable resistance element is switched between a high resistance state and a low resistance state, the bistable resistance is switched to a low resistance state. The corresponding initial initial pressures are equal. The voltage control switch according to claim 1, wherein when the bistable resistance element is switched between a high resistance state and a low resistance state, the bistable resistance is switched to a low resistance state. In the corresponding initial initial pressure, the difference between at least two initial pressures is greater than zero. A voltage controlled switch, wherein the voltage control switch comprises a bistable resistive element, the bistable resistive element comprising a polymer carrier and a plurality of metal particles dispersed in the polymer carrier; and the bistable resistive element Receiving an excitation electric field, the plurality of metal particles form a conductive path, and the bistable resistive element memorizes an initial pressure; when an absolute difference between the pressure directly acting on the bistable resistive element and the initial pressure is greater than or equal to The conductive path is broken when a minimum differential pressure is reached. A voltage controlled switch, wherein:
a bistable resistive element comprising a polymer carrier and a plurality of metal particles dispersed in the polymer carrier;
An excitation electric field generating unit that emits an electric field, the excitation electric field acts on the bistable resistance element to form the plurality of metal particles to form a conductive path and the bistable resistance element memorizes an initial pressure; and a differential pressure signal is emitted The differential pressure signal generating unit is configured to generate a differential pressure signal equal to or greater than a minimum differential pressure to disconnect the conductive path. The voltage control switch of claim 13, wherein the bistable resistance element is a film structure. The voltage control switch of claim 14, wherein the voltage control switch further comprises two electrodes disposed at opposite ends of the bistable resistance element and the bistable resistance element Electrical connection. The voltage control switch of claim 15, wherein the two electrodes are respectively disposed on opposite surfaces of the bistable resistance element. The voltage-controlled switch of claim 16, wherein the excitation electric field generating unit is electrically connected to the bistable resistance element through the two electrodes. A method of applying a voltage controlled switch includes the following steps:
Providing a bistable resistive element, the bistable resistive element comprising a polymer carrier and a plurality of metal particles dispersed in the polymer carrier;
When it is required to monitor the working pressure change of the environment in which the voltage control switch is located, an excitation electric field is applied to the bistable resistance element at the initial pressure P1 to make the bistable resistance element be in a low resistance state;
When the pressure change of the bistable resistive element exceeds the minimum differential pressure ΔP, the bistable resistive element changes from a low resistance state to a high resistance state and is maintained in a high resistance state. An alarm system, wherein:
An alarm device;
a voltage control switch for controlling an alarm of the alarm device, the voltage control switch comprising a bistable resistance element, the bistable resistance element comprising a polymer carrier and a plurality of metal particles dispersed in the polymer carrier;
An excitation electric field generating unit for applying an excitation electric field to operate the bistable resistance element in a low resistance state; and a differential pressure signal generating unit for generating a differential pressure signal to operate the bistable resistance element Resistance state.