Abstract: A resistor including a matrix formed from flexible, insulating material, and metal particles distributed uniformly inside the matrix; which resistor is characterized by the fact that the particles are obtained from mechanical machining chips produced using tools including agglomerates of abrasive granules, and which are passed over the surface of the workpiece; and which particles are magnetized by passage of the aforementioned tool over the surface of the workpiece.

Abstract: A glass membrane touch-controlled circuit apparatus for voltage selection. The apparatus has a flexible glass membrane which is spaced by a dielectric layer adhesively joined between the upper flexible glass membrane and a lower, rigid support layer. Conductive circuitry is printed onto the surface of the upper flexible glass membrane and corresponding areas of conductive and/or resistive circuitry are printed onto the lower support layer. By application of tactile pressure to the upper flexible glass membrane, the conductive circuitry printed onto the flexible glass membrane can be moved into a point of momentary contact with the circuitry carried on the lower support layer.

Abstract: Resistive position indicator has an enlongated resistive element with an electrical terminal at each end and a tap which can be brought into contact with the resistive element. A contact point divides the resistive element into two portions and is movable along the resistive element, so that the resistance ratio between the two portions of the resistive element can be varied within wide limits. The resistive element consists of a layer of resistive material applied on a substrate of electrically insulating material. The tap comprises an elongated contact portion of electrically conducting material applied on a substrate and positioned in front of, parallel to, and slightly spaced from the resistive element, so that an air gap is formed between the resistive element and the contact portion of the tap.

Abstract: A bumper for impact detection with an object is disclosed. An electrically conductive member has a compressible, electrically conductive material mounted thereto. An insulator formed of mesh material is sandwiched between the electrically conductive member and the electrically conductive material for electrically insulating the member and the material when the member is in a non-compressed state and to provide electrical conduction between the member and the material when the conductive material is in a compressed state.

Abstract: A reversible resistant device having the property of being normally non-conductive, but being adapted to being converted to the conductive state. This change in conductive state is achieved by subjecting the device to a high voltage or high electric field. The essence of the device is a normally non-conductive film located between conductive layers, the film being formed by metal oxide coated metal particles embedded in a binder. When subjected to a high a potential, the metal oxide coating loses its dielectric properties and renders the film conductive.

Abstract: A touch sensor device, and its method of operation, that provides information as to the position of a touch thereon together with information as to the amount of pressure applied to the sensor at the touch position. The device has a pair of spaced-apart membranous sheets with coatings thereon suitable for the determination of position information in a conventional manner. In addition, switching units are included which, during a given time interval of operation, supply a uniform electrical potential in one of the sheets. During that same interval contacts or electrodes on opposite edges of the second sheet are rapidly switched to alternately be oppositely connected to ground on one edge and to the information processing unit at the other edge. In this manner, there is a fixed potential applied to the contact resistance circuit created between the sheets due to the touch pressure, and the alternate switching averages the potential on the second sheet.

Abstract: A push button switch which may be used, for example, as a zooming switch in a video camera, having a uniform electrical resistance/applied pressure characteristic and which can be manufactured easily and at a low cost. The switch includes a conductive layer and a pressure-sensitive resistance element disposed between electrode patterns provided on a printed circuit board and an insulated push button. The conductive layer is coated with a pressure-sensitive conductive paste and the pressure-sensitive resistance element is fixed to the insulated push button at a opposed surface to the electrode patterns separated by a predetermined distance.

Abstract: A control device for cooking apparatus includes an input panel for inputting a desired cooking condition. The input panel includes a flexible panel on which a plurality of cooking condition set key-patterns are formed in line. When a desired cooking condition set key-pattern is pressed, the input panel produces a voltage corresponding to the pressed key-pattern. The value of this voltage is changed step by step from one side key-pattern toward the other side key-pattern on the flexible panel.

Abstract: A pressure-sensing electric conductor, has an elastic electric conductive layer made of silicone rubber, on which a flexible insulating layer made of resin having a number of holes in a form of net pattern is overlaid. The pressure-sensing electric conductor is produced by applying a silicone adhesive compound to which toluene and silicone ink are added over the flexible sheet of resin insulating layer having a number of holes, and adhering said sheet to said electric conductor formed by means of vulcanization into an elastic sheet, and by bonding them together by applying pressure to both sides of the resin insulator and electric conductor.

Abstract: An electrical control device (8) is operable by a lever (12) and includes a deformable member (50) which is deformed in response to manual pressure on the lever. The deformable member (50) has an electrically conductive surface portion (52) which is arranged to engage a continuous area or track of resistive material (62) such that as a changing manual pressure is applied to the lever (12) a changing amount of the track is electrically bridged or short circuited by said conductive surface portions (52). The resistive area or track is connected to electrical terminals (64, 66) so as to present a continuously variable electrical resistance across the terminals depending on the manual pressure applied.

Abstract: A conductor comprising a first elongated electric conducting element; a spacer element formed from insulating material and placed over the surface of the first conducting element, so as to shield all but given portions of the aforementioned surface; a second tubular electric conducting element placed over the outside of the aforementioned spacer element; a third tubular electric conducting element placed over the outside of the aforementioned second element; and a tubular insulating sheath placed over the outside of the aforementioned third conducting element.

Abstract: A conductor comprising a first and second electric conducting element, each in the form of a flat plate, and at least a third electric conducting element also in the form of a flat plate. The first and second conducting elements are arranged with one surface contacting a surface on the third conducting element; and a spacer element formed from insulating material is placed between the mating surfacese of two of the aforementioned conducting elements, so as to at least partially shield the aforementioned surfaces.

Abstract: A tactile sensor device, of value in a sensor system for identifying an object by contact, in the form of a first array of parallel elongated lengths of electroconductive material, a second array of parallel elongated lengths of electroconductive material, disposed transverse to the first array so that lengths in the two arrays intersect, and a resilient piezoresistive material disposed in continuous contact with the lengths of electroconductive material in one of the arrays and located between the arrays.

Abstract: There provided is a pressure detector accurate in operation and high in reproducibility to have a resistance circuit substrate provided with at least one pair of electrodes and forming a resistance circuit between the electrodes through printing or other means, a block contact maker formed of a conductive elastic material to a shape ready for deforming, which is characterized in that the block contact maker is kept in contact with the resistance circuit substrate at all times, the block contact maker is deformed according as the state shifts from non-pressurized to pressurized to change a contact area gradually with the resistance circuit substrate, thus forming a variable resistance circuit parallel electrically with the resistance circuit substrate.

Abstract: A deformable type variable resistor element using silicone gel with a penetration value of approximately 50 to 200 as a basic member in which electrically conductive fine particles as much as 20 to 50 weight percent are mixed, which basic member is provided with at least a pair of electrodes so that the conductive fine particles contained in the basic member come in contact each other to form a number of electrical passages between the pair of electrodes when the basic member is physically deformed by an external force.

Abstract: A vehicle sensing device comprises an electrically insulating elongate carrier (1) with two electrical conductors (2,3) extending longitudinally of the carrier and spaced apart transversely of the carrier so that there is no direct contact between the conductors. A strip (14) of elastomeric material overlies both conductors and is in contact therewith in areas distributed along substantially the whole of their length. The strip (4) being such that in the absence of a given level of applied pressure the strip forms a barrier of high electrical resistance between the conductors, and that in the presence of applied pressure above the given level in any region of the strip, that region of the strip forms an electrically conductive path between the conductors. The carrier, conductors and strip are wholly encapsulated in a jacket of water-resistance and abrasion-resistance elastomeric material.

Abstract: A resistor is formed from a structure including at least one network of electrically conductive wires, and a matrix for supporting the aforementioned structure, the matrix formed from a flexible, electrically insulating material inside which the aforementioned structure is sunk, with a number of surface portions of the wires in the aforementioned networks being separated by small gaps, the resistor being formed by a manufacturing process substantially including the steps of forming a system including a structure having at least one network of electrically conductive wires, and arranging a liquid material between the wires of the aforementioned networks in the aforementioned structure, the aforementioned liquid material being designed to assume a state in which it is both solid and flexible; and in subsequently solidifying the aforementioned material in such a manner as to form a solid, flexible matrix for supporting the aforementioned structure.

Abstract: An apparatus for varying impedance includes a first conductive member, a second member associated therewith, and a third wiper member electrically contacting the first and second members. Use of a conductive rolling member as the third wiper member minimizes wear and degradation of all members. Alternately, or in conjunction with a rolling wiper member, use of a conductive elastomer further eliminates wear.

Abstract: A pressure sensing device constructed of a high molecular conductor kept in contact at all times with at least one pair of electrodes in a circuit and wherein the resistance of the conductor is sensitive to external forces oppositely applied by an actuator and a spring. Changing of the relative value of the forces changes the conductor resistance thus changing the circuit resistance.

Abstract: A digitizer pad includes at least two base plys, each having thereon at least three terminals, a resistor ply disposed between two of the terminals with a plurality of conductors extending from each resistor ply which are spaced apart and interleaved with a plurality of conductors extending from each third terminal. The respective base plys' conducting surfaces face each other and are sandwiched about a nonconductive ply that includes a pressure sensitive conductive layer on each side, the area of which layer covers a portion of the area encompassed by the interleaved conductors on each base ply. The resistor plys and conductors on each base ply are at predetermined angles to those on the base ply, hence the conductors of each base ply form two predefined axes. A voltage source is sequentially coupled, by suitable switching means, across a selected pair of terminals on each ply to measure the selected location along the parameter dimension defined by the terminals across which the voltage source is coupled.

Abstract: Optical and digital potentiometers and controllers. In one embodiment of the invention, a paddle slider is maintained within a housing along with a light source and sensor. The amount of light received by the sensor is a function of the position of the slider and, accordingly, a control signal output may be developed corresponding to the mechanical position of the slider. In other embodiments, light sources are caused to impinge on reflective surfaces which reflect the light through a film onto additional reflective surfaces which direct the light to a sensor. The film may be of varying optical density along the length thereof such that the amount of light received corresponds to the position of the slider, or the film may be digitally encoded such that separate light beams received by the sensor will correspond to a digital position of the slider. In another embodiment, a cylindrical digitally encoded film is rotated between a light source and sensor, thereby varying the output of the sensor.

Abstract: A key-touch sensor has an electric circuit formed on a first electrically insulating substrate covered with a carbon electrode, an electric circuit formed on a second electrically insulating substrate covered with a carbon electrode which is opposed to the electric circuit on the first substrate across a gap, and a pressure-sensitive electroconductive layer deposited to at least one of the first or second substrates and disposed to fill the gap.

Abstract: A coaxial cable pressure sensor having a partially conductive layer of fibres or particles between the inner and outer coaxial conductors whereby pressure applied to the sensor produces a detectable change in resistance of the circuit passing through the partially conductive layer. One or more of the sensors may be incorporated into a vehicle weighing system, preferably in the form of a portable "mat" which may be folded or rolled up.

Abstract: A liquid or gel filled pillow utilized for therapeutic purposes is formed from a pair of flexible casing of plastic or the like, one within the other, and being separated by a compressible electrically conductive foam material having a high resistance in its uncompressed slate and a low resistance when compressed. The facing surfaces of the casings are coated with a layer of highly conductive material in electrical contact with the foam. The inner casing is provided with a thermostatically controlled heating element for heating the liquid or gel contained therein. One terminal of the heating element is connected to the power supply through the conductive layers foam so that upon compression of the foam, as would be occasioned by a patient laying his head upon the pillow, there will result an electric current flow to the heating element due to the lowered electrical resistance of the foam.

Abstract: A pressure sensing device utilizing force transducer ink comprises a resistive region deposited between a first and a second conducting region on a first insulating material, the resistive region electrically coupling the two conducting regions. On a second insulating material, a conducting region is deposited and a layer of force transducer ink is deposited over the conducting region. The two insulating materials are positioned in such a manner that the pressure transducer ink is in contact with the resistive region and separates the resistive and coupled conducting regions from the conducting region. A determination of the force applied to this configuration can be made by measuring the resistance between the first and second conducting regions. According to a second embodiment, a second resistive region and coupled conducting regions replace the conducting region on the second insulating material.

Abstract: This invention pertains to gauge apparatus for measuring liquid levels comprising an elongated electrical sensor adapted to be arranged in upright position while immersed so constructed as to have an electrical resistance which may be varied. The sensor is fabricated by providing a rigid elongated support and securing an elongated array of resistors thereto. A flexible layer of conductive material is then applied to the surface of a sheet of flexible insulated material after which the sheet is secured to the support with the conductive material facing the resistors. After the sheet is secured to the support, it is heated, whereby the sheet will return to a position in spaced relation from the resistors. Further, an elongated planar magnet is secured to the rigid support on the side facing the sheet. The magnet is polarized such that the surface facing the sheet has elongated contiguous opposite poles joined along a straight line. The array of resistors is mounted on the magnet surface.

Abstract: An elastomeric electro-conductive device (10) capable of providing within a predetermined range of elastic elongation (.lambda.) of the device (10) sensory signals representative of elastic elongation (.lambda.) imposed on the device includes an elastomeric electro-conductive member (11) bonded to an elastomeric substrate (12). Member (11) and substrate (12) have substantially similar resistance-to-stretch characteristics .phi. within the predetermined range. On a Mooney Plot for (.lambda..sup.-1) values in the range 0.5 to 0.8 .phi. is substantially constant at 0.4 M Nm.sup.-2.

Abstract: Objects contacted by mechanical fingers cause shunts that are touched at a position to contact resistance strips. Sensing resistance remaining between the shunt contact and one end of the resistance strip indicates position of contact along the finger. Shapes and alignments of objects are sensed by comparing positional information along several fingers.

Abstract: A piezoresistive force-measuring element comprises at least two force-introduction plates with an electrical conductor subjected to plastic deformation arranged between them. The force-introduction plates transmit the forces acting on them without mechanical shunting onto the conductor between them. The change of electrical resistance caused by the force sustained can be used to measure force, accompanied by plastic as well as elastic deformation of the conductor. The typically annular or rectangular force-introduction plates can be fitted inside a housing which may include a bridge circuit for determining the resistance change as well as other electronics enabling the device to be used as a transmitter. By placing the conductor in grooves or anchoring it in the pores of the adjacent plates, an essentially hydrostatic loading of the conductor is obtained, bringing an enormous extension of the measuring range while the measuring accuracy is enhanced owing to the reduced hysteresis.

Abstract: A digitizer pad includes at least two sets of terminals where each set has at least a first and second terminal positioned to define a parameter dimension therebetween. A resistor ply is disposed between the terminals of each set. The resistor ply has an electrical contact surface with a resistance gradient profile between the terminals in each set. An output terminal is electrically interconnected to a selected location along the contact surface of the resistor ply. A voltage source is sequentially coupled, by suitable switching means, across a selected subset of terminals in each set of terminals whereby the voltage at the output terminal is a measure of the selected location along the parameter dimension defined by the terminals across which the voltage source is coupled.

Abstract: An anisotropically conductive adhesive composition (10) for use in electrically connecting at least one conductive area (14) on one substrate (12) with at least one conductive area (20) on a second substrate (18) is disclosed. The composition (10) is comprised of a mixture of conductive particles and a nonconductive adhesive binder (26). The conductive particles are dispersed throughout the binder in a plurality of noncontiguous conductive units (24) such that, upon applying a layer (30) of the composition (10) over both the conductive and insulating areas (14, 16) on one substrate (12) and positioning in a conducting relationship and adhering said at least one conductive area (20) on the second substrate (18) with said at least one conductive area (14) on the first substrate (12), the units (24) establish electrical connection between the adhered conductive areas (14, 20) on the two substrates (12, 18).

Abstract: The deformation sensitive electroconductive knitted or woven fabric of the present invention is a knitted or woven fabric, which can be changed in electroconductivity at the deformed portion when the deformation of stretch or compression is applied thereon by maintaining in the certain ratio of the number of electrically insulating portions to the number of electroconductive portions at the intertwined portions of the fibers and/or the portions between the intertwined portions of the fibers. By using this knitted or woven fabric directly or a deformation sensitive electroconductive sheet having an elastomer laminated on at least one surface of the knitted or woven fabric, it can be utilized as an stretch sensitive electroconductive device or pressure sensitive electroconductive device provided electrodes capable of detecting the changes in electroconductivity corresponding to deformations as electrical characteristics such as electrical resistance.

Abstract: A low cost sensor is described. The sensor is responsive to the component of a force applied to the sensor relative to an axis of the sensor. The sensor comprises rigid, spaced-apart support members. At least one pair of electrically-conductive elements are positioned to move with the support members in response to the force, contact and compress against one another as the force component varies relative to the axis such that the electrical impedance between the two elements changes as said component of force changes.

Abstract: An apparatus for detecting, for example, the disconnection of signal lights such as flashers for vehicles and for warning of this disconnection has a detecting resistor element for converting an ON current of the signal lights into a voltage signal. The voltage signal detected by this resistor element is compared with a reference voltage which is set at a discrimination/oscillation control circuit so as to detect if the detecting voltage signal is lower than the reference voltage. When such a state is detected, the oscillation frequency of an oscillator for changing the flashing frequency of the signal light is doubled. The disconnection of the lights can be detected by observing the frequency of the flashing signal. The detecting resistor element consists of a resistive wiring formed of a resistive material which is processed so as to have a smaller resistance than desired.

Abstract: A multi-layered tactile sensing skin is provided for a robotic arm or the like. The skin includes adjacent layers of electrically insulative film having opposed contiguous surfaces. An electrically conductive carbon based compound is applied uniformly to one of the surfaces, while the other surface is selectively coated with silver oxide to form a series of pairs of first and second electrically conductive regions separated from one another by a dielectric gap. The carbon based conductor bridges the gap betwen the conductive regions in each pair, permitting flow of electrical current between the regions. The current flow increases with an increase in pressure over the interface between the layers of film, and the amperage increase can be utilized to trigger a signal to the robot power supply, to decelerate, stop or reverse arm movement.

Abstract: The invention comprises a variable linear resistor. It comprises a first plate having a recessed area cut into one face and a second plate parallel to and facing the face of the first plate with the recessed area. A length of elastic tubing is disposed in the recessed area. The distance between the two plates is adjustable, and this allows for the compression of the elastic tube.

Abstract: An input device of the tablet type comprising opposed planar resistance bodies with a plurality of dot spacers interposed therebetween, plate-like insulating bodies made of soft and elastic material and provided respectively and integrally on the outsides of the planar resistance bodies, and a fixed plate for securing and supporting one of the plate-like insulating bodies, and characterized in that a plurality of cavities are formed in an abutment area between the one plate-like insulating body and the fixed plate by which each dot spacer portion can sink when a force is applied, whereby entry of information relating to the dot spacer portion also is allowed.

Abstract: A media thickness compensating device for a printer which senses the thickness of each record medium, e.g., a printing sheet, mounted on a platen to maintain a proper printing gap between the record medium and a print head. In this device, sensing means including a pressure-sensitive conductive rubber member is disposed so as to be movable toward and away from the platen. The movement of the print head is compensated in accordance with the displacement of the sensing means moved from a reference position to a position where the sensing means comes into contact with the record medium to cause the resistance of the pressure-sensitive conductive rubber member to reach a predetermined reference value. Thus, the printing gap can be kept proper at all times.

Abstract: A transducer responsive to rotational movement comprises a support member on which a shaft is rotatably mounted. Relative movement between the member and the shaft is sensed by flexure of a strip of a piezo-resistive mateial. Typically, the strip is facribed from signle crystal silicon.

Abstract: A sensitive, durable, high resolution tactile sensor particularly suited for use as a robot end effector in an automated manufacturing process. The tactile sensor has an array of pressure sensing sites provided by a series of current emitter electrodes surrounded by a series of companion current collector electrodes both of which engage a rough conductive layer carried on the underside of a resilient platen. The emitters are electrically connected together in parallel rows, and the collectors are electrically connected together in parallel columns above and across the rows. The emitters and collectors are electrically insulated from one another as are the rows and columns. When the platen engages an object to apply pressure at one of the sites, and a positive voltage is applied to an emitter electrode, current flows from the emitter electrode and through the conductive layer to the companion collector electrode from which it is collected and measured.

Abstract: The invention relates to such signal transmitters for electrical signals which comprise an elastic body (1) consisting of an elastomer matrix containing carbon black as a filling agent. The invention solves the problem of extending the field of use of such signal transmitters and is based on the realization that this is attained if the elastic body is arranged so that, when deformed, it will be subjected to bending rather than compression. The carbon black should be of the structure-forming type and present in an optimized concentration interval, generally about 5-15 parts counted on 100 parts of the elastomer.

Abstract: A touch control apparatus for an electronic keyboard instrument, comprises a sensor having: an elongated insulating sheet having a set of conductive pattern films on a surface thereof, the elongated insulating sheet being folded and the set of conductive pattern films being formed to be spaced apart from each other; and a pressure-sensitive element sandwiched in a space defined by the folded elongated insulating sheet to be in contact with the conductive pattern films. The pressure sensitive element is deformed when a key of the instrument is depressed to deliver an electrical output through the conductive films representing the magnitude of the key depression. The apparatus is superior in easiness of handling the sensor and of assembling the apparatus.

Abstract: A method for inspecting printed wiring boards which comprises superposing, on a printed wiring board to be inspected, a pressure-sensitive, electroconductive, elastic sheet, any portions of which become electroconductive in the direction of thickness of the elastic sheet when the portions have been pressed in the same direction, pressing the elastic sheet at portions corresponding to the electroconductive portions of said board by the use of inspecting electrodes, thereby electrically connecting the corresponding inspecting electrodes to the intended electroconductive portions of the printed wiring board.

Abstract: A touch tablet is provided containing two sheets of insulating material each of which contains a plurality of spaced apart conductive lines. A resistive strip on each sheet contacts and connects electrically one end of each of the plurality of conductive lines on that sheet. Each resistive strip functions as a potentiometer. Mounted between the two sheets and spaced apart therefrom is a conductive middle sheet. The first and second sheets are mounted such that the first and second sets of a plurality of conductive lines on these sheets are orthogonal to each other. A user presses on one of the two sheets to bring all three sheets into contact. The impedence of each potentiometer is a function of the contact point. The potentiometer is used as part of an RC circuit to provide a variable time constant representative of the coordinate of the contact point.

Abstract: An electric tool, especially a hand tool, is provided with a torque monitor. For this purpose the support bearings taking up the reaction torque of the electric motor in the housing of the tool are equipped with pressure sensors in the form of conductive plastic material, the electric resistance of which changes as a function of the pressure exerted.

Abstract: An input device for use in a display unit serving as a terminal of a computer has first and second insulating sheets and an insulating spacer sandwiched between the first and second sheets. The first sheet has first terminal leads on its both ends, while the second sheet has second terminal leads which extend in perpendicular relation to the first terminal leads. The upper surface is covered with a flexible, insulating, protective sheet. The spacer includes lattice-like conductors and consists of a material having cells of gas and elasticity and flexibility such as silicone foam. A fixed voltage is alternately applied across both ends of the first sheet and across both ends of the second sheet. When the protective sheet is depressed at a point P as by a depression pen, the position of the point is measured and represented by means of X- and Y-coordinates.

Abstract: The flexible force sensor having an electrical conductor releasably attachable to a test site and a plurality of relatively spaced electrical contacts supported for varying contact with the conductor such that when a force is applied to the force sensor, the electrical contacts and electrical conductor move into and out of varying areas and/or paths of electrical contact to produce electrical resistances therebetween corresponding to the extent of such areas and/or paths and as a function of the applied force.

Abstract: A layer of carbon fiber materials sandwiched between two conductive layers provides a tactile feedback sensor which is particularly useful in manipulator systems for robotics and assembly automation.

Abstract: A touch-controlled apparatus of the type in which two parts of a circuit component are selectively brought into contact, which includes plural circuit components. In one embodiment the two components (at least one of which must be a potentiometer) are co-planar and longitudinally aligned. In another embodiment two co-planar potentiometers are disposed in parallel side-by-side relation so as to be simultaneously actuated by the same touch pressure. In a third embodiment two or more components are disposed in two different stacked layers for simultaneous or sequential operation. An improved sample and hold output circuit includes only a parallel capacitor, or a series resistor and parallel capacitor, connected to one part of a circuit component. The component may be formed as three folded sections of a single sheet-like member, the sections being foldable into a three-tiered stack.

Abstract: A tactile sensor for sensing an object in contact therewith. In its preferred form, the sensor comprises a plurality of layers disposed in a sandwich arrangement. A top layer is comprised of a flexible, electrically-insulating material and a plurality of parallel flexible conductive rods. A bottom layer is comprised of an electrically-insulating material and a plurality of parallel conductive rods that extend at right angles to the conductive rods of the top layer, thus forming a sensory array comprising a plurality of superimposed intersection points arranged in a grid pattern. An intermediate layer is comprised of a resilient, electrically-insulating material in which is disposed a plurality of parallel conductive posts that extend perpendicular to the plane of the three layers. These posts are comprised of a resilient conducting material.