Abstract: A sensor unit is provided and includes a first substrate, first and second electrodes, an input portion disposed so that a gap exists between the substrate and the input portion, a plurality of first structures disposed in the gap and extending at least partially between the first substrate and the input portion, and a second insulating structure disposed on a side of the first structures that is away from the input portion, or between adjacent first structures. The sensor unit is configured to detect a change in capacitance between the first and second electrodes upon a change in position of the input portion relative to the first substrate.

Abstract: The capacitive measuring circuit for a moved elongated test material contains at least two measuring capacitors, each of which is configured for receiving the test material. It further contains electrically actuatable selection means, by means of which one of the measuring capacitors can be selected in such a way that only the selected measuring capacitor contributes to the measurement, whereas the other measuring capacitors do not. As a result, the total capacitance of the measuring circuit is reduced and its sensitivity is increased.

Abstract: Strain sensing may be provided. First, a strain threshold for a circuit board may be determined. Then a strain capacitor may be selected that will fail when the circuit board is subjected to the strain threshold while the strain capacitor is mounted on the circuit board. The strain capacitor may be ceramic and may be in a commercially available size. The strain capacitor may then be mounted to the circuit board and monitored for failure.

Abstract: Disclosed is a detection device for detecting a strength and a direction of an external force applied to a reference point, the detection device including: a first substrate having a plurality of first capacitor electrodes arranged around the reference point; a second substrate arranged to face the first substrate by interposing the first capacitor electrodes; a dielectric body arranged between the first and second substrates and made of an elastic body or fluid; a second capacitor electrode arranged to face the first capacitor electrodes by interposing the dielectric body between the first and second substrates; and a third substrate having an elastic projection which has a gravity center in a location overlapping with the reference point and is elastically deformed by the external force while a tip thereof abuts on the second substrate.

Abstract: A device can have an electrostatic MEMS actuator and a capacitive sensor in electrical communication with the electrostatic MEMS actuator. The capacitive sensor can be configured to determine a capacitance of the electrostatic MEMS actuator while a force is being applied to the electrostatic MEMS actuator as the electrostatic MEMS actuator is being actuated. The device can be used to construct a keyboard having tactile feedback, for example.

Abstract: A triboelectric generator includes a first contact charging member, a second contact charging member and an electrical load. The first contact charging member has a contact side and an opposite back side. The first contact charging member includes a material that has a first rating on a triboelectric series and also has a conductive aspect. The second contact charging member has a second rating on the triboelectric series, different from the first rating, and is configured to come into contact with the first contact layer and go out of contact with the first contact layer. The electrical load electrically is coupled to the first contact charging member and to a common voltage so that current will flow through the load after the second contact charging member comes into contact with the first contact charging member and then goes out of contact with the first contact charging member.

Abstract: A linear sensor 21 includes an attachment base 22 attached to a metallic edge of a slide door 2 capable of opening and closing a platform 4, a skin cover part 23 which bulges from the attachment base 22 and has a hollow part 24 in the inside, an insulator 25 which has flexibility and also is embedded in the hollow part 24, and a plate-shaped electrode 26 opposed to the attachment base 22, at least a portion of the electrode being embedded in the insulator 25. In the hollow part 24, a gap 27 is disposed between the electrode 26 and the attachment base 22 and also, the electrode 26 is set in a plus pole and the attachment base 22 is set in a minus pole as the grounding, and proximity and/or contact between a foreign body and the skin cover part 23 is detected based on a change in capacitance between the electrode 26 and the grounding minus pole.

Abstract: A testing instrument for mechanical testing at nano or micron scale includes a transducer body, and a coupling shaft coupled with a probe tip. A transducer body houses a capacitor. The capacitor includes first and second counter electrodes and a center electrode assembly interposed therebetween. The center electrode assembly is movable with the coupling shaft relative to the first and second counter electrodes, for instance in one or more of dimensions including laterally and normally. The center electrode assembly includes a center plate coupled with the coupling shaft and one or more springs extending from the center plate. Upper and lower plates are coupled with the center plate and cover the center plate and the one or more springs. A shaft support assembly includes one or more support elements coupled along the coupling shaft. The shaft support assembly provides lateral support to the coupling shaft.

Abstract: A floating element shear sensor and method for fabricating the same are provided. According to an embodiment, a microelectromechanical systems (MEMS)-based capacitive floating element shear stress sensor is provided that can achieve time-resolved turbulence measurement. In one embodiment, a differential capacitive transduction scheme is used for shear stress measurement. The floating element structure for the differential capacitive transduction scheme incorporates inter digitated comb fingers forming differential capacitors, which provide electrical output proportional to the floating element deflection.

Abstract: An integrated low-noise sensing circuit with efficient bias stabilization in accordance with the present invention comprises a first capacitance sensing element, a second capacitance sensing element, a sub-threshold transistor and an amplifier circuit wherein the first stage is an input transistor. The second capacitance sensing element is connected to the first capacitance sensing element. The sub-threshold transistor comprises a body, a gate, a source, a drain, a source-body junction diode and a bulk. The gate forms on top of the body. The source forms on the body and is connected to the first capacitance sensing element and the second capacitance sensing element. The drain forms on the body and is connected to the gate and the amplifier output terminal. The source-body junction diode comprises an anode and a cathode. The anode is connected to the ground.

Abstract: A testing instrument for mechanical testing at nano or micron scale includes a transducer body, and a coupling shaft coupled with a probe tip. A transducer body houses a capacitor. The capacitor includes first and second counter electrodes and a center electrode assembly interposed therebetween. The center electrode assembly is movable with the coupling shaft relative to the first and second counter electrodes, for instance in one or more of dimensions including laterally and normally. The center electrode assembly includes a center plate coupled with the coupling shaft and one or more springs extending from the center plate. Upper and lower plates are coupled with the center plate and cover the center plate and the one or more springs. A shaft support assembly includes one or more support elements coupled along the coupling shaft. The shaft support assembly provides lateral support to the coupling shaft.

Abstract: A method of damping control for a nanomechanical test system, the method including providing an input signal, providing an output signal representative of movement of a displaceable probe along an axis in response to the input signal, performing a frequency-dependent phase shift of the output signal to provide a phase-shifted signal, adjusting the phase-shifted signal by a gain value to provide a feedback signal, and adjusting the input signal by incorporating the feedback signal with the input signal.

Abstract: Sensing device and sensing method are disclosed. The multi-dimensional force sensing device includes a soft laminose dielectric structure, a conductive sheet, at least one first electrode sheet, at least one second electrode sheet, a measuring unit and an analysis unit. The soft laminose dielectric structure has a first surface and a second surface opposite to each other. The conductive sheet is disposed on the first surface and has a vertical projection area. The first electrode sheet is disposed on the second surface and totally in the range of the vertical projection area. The second electrode sheet is disposed on the second surface and partially in the range of the vertical projection area. The analysis unit analyzes the magnitude and direction of a force applied on the conductive sheet according to the capacitance between the at least one first electrode sheet and between the first and the second electrode sheets.

Abstract: Three or more electrodes are arranged on either a window frame or window glass of an automobile. An electric field measurement unit measures the capacitance between various combinations of the electrodes to detect whether an object is located between the window frame and window glass. A control circuit varies the sensitivity of the electric field measurement unit by switching amongst the electrodes used for capacitance measurement based on the movement and position of the window glass.

Abstract: A small, high-stiffness torque sensor. An annular deformable body is disposed between left and right side supports. Convex sections protruding from the left side support in a rightward direction are joined to the left side surface of the annular deformable body, and convex sections protruding from the right side support in a leftward direction are joined to the right side surface of the annular deformable body. When force is applied to the right side support and torque around the Z axis acts on the left side support, the annular deformable body is elliptically deformed and the long-axis position of the inner peripheral surface of the annular deformable body moves away from the Z axis while the short-axis position moves closer to the Z axis. The acting torque is detected as a variation in the capacitance value of capacitive elements formed by displacement electrodes and fixed electrodes.

Abstract: The present invention discloses an MEMS sensor and a method for making the MEMS sensor. The MEMS sensor according to the present invention includes: a substrate including an opening; a suspended structure located above the opening; and an upper structure, a portion of which is at least partially separated from a portion of the suspended structure; wherein the suspended structure and the upper structure are separated from each other by a step including metal etch.

Abstract: A capacitive strain sensor for sensing strain of a structure. The sensor includes a first section attached to the structure at a first location and a second section attached to the structure at a second location. The first section includes a capacitor plate electrically isolated from the structure and the second section includes two electrically isolated capacitive plates, both of the plates being electrically isolated from the structure. A flexible connector connects the first section to the second section. The capacitor plate of the first section is separated from the two capacitive plates of the second section by at least one capacitive gap. When strain is experienced by the structure, a change occurs in the capacitive gap due to relative motion between the first and second sections.

Abstract: A capacitive strain sensor for sensing strain of a structure. The sensor includes a first section attached to the structure at a first location and a second section attached to the structure at a second location. The first section includes a capacitor plate electrically isolated from the structure and the second section includes two electrically isolated capacitive plates, both of the plates being electrically isolated from the structure. A flexible connector connects the first section to the second section. The capacitor plate of the first section is separated from the two capacitive plates of the second section by at least one capacitive gap. When strain is experienced by the structure, a change occurs in the capacitive gap due to relative motion between the first and second sections. The first section includes a core and the second section includes a ring that receives the core.

Abstract: A sensing element for sensing the softness of an object by abutting the sensing element against the object and biasing the sensing element toward the object with a biasing force. The sensing element includes a deformable section, the deformable section being deformable between an undeformed configuration and a deformed configuration, the deformed configuration being achievable when the deformable section is abutted against and biased toward the object; a deformation sensor operatively coupled to the deformable section for sensing a deformation of the deformable section between the deformed and undeformed configurations; and a force sensor operatively coupled to the deformable section for sensing the biasing force exerted onto the deformable section by the object when the deformable section is biased toward the object with the biasing force.

Abstract: A contact detection apparatus that allows faster detection and a pinch prevention apparatus equipped with such a detection apparatus are provided. The contact detection apparatus includes a first electrode (430) made of a flexible conductive material and extending throughout a contact detection range, a second electrode (440) apart from the first electrode and extending on the back side of the first electrode, and detection means for detecting contact of an object with the first electrode based on the capacitance of the first electrode. The first electrode is made of a conductive resin containing an embedded conductor.

Abstract: An anti-entrapment system for preventing an object from being entrapped by a translating device such as a vehicle window includes a capacitance sensor and a controller. The sensor has a jacket with a cavity, a dielectric element within the cavity, and first and second electrical conductors. The conductors are within the cavity on opposite sides of the dielectric element such that the conductors are separated from one another by a separation distance. The capacitance of the sensor changes in response to an electrically conductive object moving in proximity to at least one of the conductors. The controller is configured to control a translating device as a function of the capacitance of the sensor. The jacket is attachable to a seal configured to receive the translating device.

Abstract: A test system for testing a capacitive touch sensor is provided. The test system includes a resistor, a signal generator and a micro controller. A first end of the resistor is electrically connected to a sensing port of the capacitive touch sensor. The signal generator provides a test voltage to a second end of the resistor according to control information. In this way, the resistor generates a test current according to the test voltage, and the capacitive touch sensor provides a voltage difference to the sensing port according to a plurality of switching signals, and converts the test current into test information. The micro controller generates the control information according to a test table, and compares the test information according to the test table, so as to determine whether an operation of the capacitive touch sensor is normal.

Abstract: An actuatable capacitive transducer including a transducer body, a first capacitor including a displaceable electrode and electrically configured as an electrostatic actuator, and a second capacitor including a displaceable electrode and electrically configured as a capacitive displacement sensor, wherein the second capacitor comprises a multi-plate capacitor. The actuatable capacitive transducer further includes a coupling shaft configured to mechanically couple the displaceable electrode of the first capacitor to the displaceable electrode of the second capacitor to form a displaceable electrode unit which is displaceable relative to the transducer body, and an electrically-conductive indenter mechanically coupled to the coupling shaft so as to be displaceable in unison with the displaceable electrode unit.

Abstract: An anti-entrapment system for preventing an object from being entrapped by a translating device such as a vehicle window includes a capacitance sensor and a controller. The sensor has a jacket with a cavity, a dielectric element within the cavity, and first and second electrical conductors. The conductors are within the cavity on opposite sides of the dielectric element such that the conductors are separated from one another by a separation distance. The capacitance of the sensor changes in response to an electrically conductive object moving in proximity to at least one of the conductors. The controller is configured to control a translating device as a function of the capacitance of the sensor. The jacket is attachable to a seal configured to receive the translating device.

Abstract: The measuring method is for measuring a physical parameter using an electronic interface circuit (1) for a capacitive sensor (2) with at least two capacitors (C1X, C2X) whose common electrode (CM) is mobile between the fixed electrodes. The electronic circuit includes an amplifier (4) connected to the common electrode (CM) by a switching unit (3), a logic unit (5) connected to the amplifier for supplying first and second digital measuring signals, and a digital-analogue converter (7) for supplying a measurement voltage (VDAC) to the electrodes on the basis of a conversion of one of the digital signals.

Abstract: The present invention relates to an entrance barrier comprising a barrier element movable between an open and a closed position, driving means, by which the barrier element can driven from one position to the other position respectively, a control unit, by which the driving means are controllable, and a sensor unit connected to the control unit. The invention also relates to a barrier element for the entrance barrier and to method for operating the entrance barrier. To provide a possibility of further improving the safety of persons in the area of entrance barriers beyond the mere passive safety of the entrance barrier, the invention proposes for the sensor unit to include a capacitive sensor.

Abstract: A strain sensor device for measuring loads on aircraft landing gear. This is done by measuring strains in the lower end of the strut, by which we infer the loading in the entire landing gear structure. These strains can be very large (as high as 10,000 microstrain) and can be imposed in numerous random directions and levels. The present invention includes a removable sensor assembly. An electromechanical means is presented that can accommodate large strains, be firmly attached to the strut, and provide good accuracy and resolution.

Abstract: Provided are capacitive strain sensors. In certain embodiments, the capacitive strain sensor can continuously and accurately measure strain in corrosive ambient conditions and may operate up to 370° C. or more in air. The sensor includes a differential capacitor that includes a bending beam structure. In some instances, the sensor is configured to increase the effect of strain in a substrate along a sensing axis while attenuating the effect of cross-axis strain. Also provided are methods of making the capacitive strain sensors, e.g., using Micro-Electro-Mechanical System (MEMS) fabrication techniques, and methods of using the capacitive strain sensors.

Abstract: An apparatus adapted for mounting on a head protector including sensor means for sensing the presence of a head in the head protector. The sensor means includes first and second spaced apart electrode elements adapted to sense the dielectric of a head and the one or more electrode elements include a fastener for fastening an object to the head protector.

Abstract: A capacitance pressure mapping system includes a plurality of sensor cells created by the intersection of electrode columns and rows, and a solid elastomer dielectric separating the electrode columns and rows. The elastomer is at least one planar sheet having a surface comprising a pattern of projections. There may be two sheets having opposing patterns of projections. The opposing patterns may be interlocking or corresponding.

Abstract: A flexible pressure sensor has a first set of substantially parallel conductors in the x direction, a second set of substantially parallel conductors in the y direction, and a composite material disposed between the first set and second set of conductors. The composite material is capable of returning to substantially its original dimensions on release of pressure. The composite material includes conductive particles at least partially embedded in an elastomeric layer that have no relative orientation and are disposed within the elastomeric layer for electrically connecting the first set and second set of conductors in the z direction under application of sufficient pressure there between.

Abstract: A method and apparatus to detect the presence of a material at a sensing device and to determine whether the material is a first material having a first material property or a second material having a second material property.

Abstract: An area-variable type capacitive displacement sensor includes: a stationary element; a movable element; an elastic member for providing a force biasing one of the stationary element and the movable member towards a remaining one thereof in a direction perpendicular to a driving direction so that the stationary element and the movable member are maintained in close contact with each other; a power supply; and a signal detecting circuit. The sensor further includes a guide means for correcting an initial alignment error and reducing an operation alignment error between the stationary element and the movable element.

Abstract: An industrial roll includes: a substantially cylindrical core having an outer surface and an internal lumen; a polymeric cover circumferentially overlying the core outer surface; and a sensing system. The sensing system includes: a plurality of sensors at least partially embedded in the cover, the sensors configured to sense an operating parameter of the roll and provide signals related to the operating parameter; and a processor operatively associated with the sensors that processes signals provided by the sensors.

Abstract: A method and system of thermal effect and off-center load compensation of a sensor are disclosed. In one embodiment, a sensor includes a first conductive surface and a second conductive surface substantially parallel to the first conductive surface, a processing and communication zone of the first conductive surface and the second conductive surface having circuitry to enable communication with an external system (e.g., using a Universal Serial Bus (USB) interface) and a sensing area having partially a ceramic substrate surrounding a sensor surface and a reference surface of the first conductive surface and the second conductive surface. The sensor may include a set of electrical leads that enable the sensing area to communicate with the processing and communication zone and with external devices, and a guard ring surrounding the first conductive surface and the second conductive surface to minimize an effect of stray capacitance.

Abstract: Described herein are processing techniques for fabrication of stretchable and/or flexible electronic devices using laser ablation patterning methods. The laser ablation patterning methods utilized herein allow for efficient manufacture of large area (e.g., up to 1 mm2 or greater or 1 m2 or greater) stretchable and/or flexible electronic devices, for example manufacturing methods permitting a reduced number of steps. The techniques described herein further provide for improved heterogeneous integration of components within an electronic device, for example components having improved alignment and/or relative positioning within an electronic device. Also described herein are flexible and/or stretchable electronic devices, such as interconnects, sensors and actuators.

Abstract: A capacitive transducer of multi-layer construction includes at least one rotor plate supported by flexible springs, A number of improvements are disclosed including a hollow rotor plate structure for reduced moving mass, buckling resistant features for the springs, improved spring anchor joint design for reduced creep and hysteresis, and material selection and matching for reduced thermal sensitivity. one embodiment allows measurement of force and/or displacement in multiple directions.

Abstract: A capacitively-coupled strain sensor and methods are presented in which the strain on a structure is measured by the varying capacitance created by the displacement of one or more boards attached to the structure.

Abstract: An anti-pinch sensor (10,13,40,45) with an associated evaluation circuit (33,48) is disclosed, which is suitable in particular for recognizing an obstacle in the way of an actuating element (e.g., 9) of a motor vehicle (1). The anti-pinch sensor (10,13,40,45) comprises a sensor body, which contains a sensing electrode (17), for generating an external electric field with respect to a counter-electrode (25), and a pressure sensor (34,34?) decoupled from the sensing electrode (17), for detecting a mechanical pressure.

Abstract: In one aspect, the present invention relates to a pressure sensing/force generating device comprising a non-planar substrate, a printed pressure sensitive element comprising (a) a piezoelectric material containing ink composition capable of producing a piezoelectric effect/piezoresistive effect and/or (b) a dielectric material containing ink composition capable of producing a capacitive effect. It also includes a first printed electrode comprising a conductive ink composition, and a second printed electrode comprising a conductive ink composition. The first and second electrodes are in electrical contact with the printed pressure sensitive element. The first and second printed electrodes and the printed pressure sensitive element collectively form a pressure sensitive junction, which is coupled to the non-planar substrate. The present invention further relates to medical devices comprising the pressure sensing/force generating device and methods of making such devices.

Abstract: A capacitive sensor core with flexible hinge includes a main grid plate, an auxiliary grid plate, and a mechanical structure transferring the measuring quantity to the displacement between the main grid plate and the auxiliary grid plate, the mechanical structure includes a stationary element and a moving element, the auxiliary grid plate and the main grid plate are fixed to the driven portion of the moving element and the corresponding position of the stationary element respectively, the stationary element and the moving element are connected through a flexible hinge; the flexible hinge consists of at least two supporting spring leafs, one end of each of the supporting spring leafs is connected to the stationary element, the other end is connected to the moving element; the plane of each of the supporting spring leafs is perpendicular to the planes of the main and auxiliary grid plates.

Abstract: A sensor for monitoring loads in a landing gear torque linkage includes a main pin having an axial interior bore defined therein. The main pin is configured and adapted to engage a torque link to a strut lug of a landing gear strut. A core pin is mounted axially within an interior bore of the main pin and is spaced radially inwardly from the interior bore for relative displacement with respect to the main pin. A capacitor is included having an inner capacitor plate mounted to the core pin. An outer capacitor plate is mounted to the main pin. Relative displacement of the core pin and the main pin due to loads acting on the torque link and strut lug results in relative displacement of the inner and outer capacitor plates. Signals can thereby be produced indicative of the loads acting on the torque link.

Abstract: A high sensitivity strain sensor that utilizes a micro-scale cavity built in a multi-layer structure, with a pair of interdigitalized capacitor incorporated on one of the layers, is described in this document. The device's capacitance changes produced by unattended deformations of the cavity can be used to measure the associated strain without using any movable electrodes. The sensor can be remotely energized from a radio frequency wave sent by a reader antenna to construct a battery-free wireless instrument. Changes on the sensor's resonant frequency are remotely detected so that a strain level is measured from fluctuations in the received signal. This detection method provides a simple, reliable and sensitive technique to measure small strain changes down to the pico-scale. Materials with a highly strain-dependant permittivity are integrated in the sensor to enhance its sensitivity. The proposed sensor consists of a simple planar structure.

Abstract: A capacitive strain sensor for sensing strain of a structure. The sensor includes a first section attached to the structure at a first location and a second section attached to the structure at a second location. The first section includes a capacitor plate electrically isolated from the structure and the second section includes two electrically isolated capacitive plates, both of the plates being electrically isolated from the structure. A flexible connector connects the first section to the second section. The capacitor plate of the first section is separated from the two capacitive plates of the second section by at least one capacitive gap. When strain is experienced by the structure, a change occurs in the capacitive gap due to relative motion between the first and second sections.

Abstract: A capacitive strain sensor for sensing strain of a structure. The sensor includes a first section attached to the structure at a first location and a second section attached to the structure at a second location. The first section includes a capacitor plate electrically isolated from the structure and the second section includes two electrically isolated capacitive plates, both of the plates being electrically isolated from the structure. A flexible connector connects the first section to the second section. The capacitor plate of the first section is separated from the two capacitive plates of the second section by at least one capacitive gap. When strain is experienced by the structure, a change occurs in the capacitive gap due to relative motion between the first and second sections. The first section includes a core and the second section includes a ring that receives the core.

Abstract: The mechanical test apparatus is a fixture utilizing capacitive gauge sensors, located in close proximity to a test specimen, to measure strain in miniature specimens. The upper collar is connected to the upper bolt which is connected to the cross head of the mechanical test machine and the lower collar is attached to the lower bolt which is attached to the load cell. The collars contain conductive target plates and capacitive gauge sensors oriented to form the two plate electrodes of a capacitor. These plates are precisely positioned and move as a mechanical test is performed. The measured voltage is proportional to the distance between the plates, thus allowing the strain to be calculated. The system can be configured to perform tensile, compression, and bending tests at submicron tolerances.

Abstract: A floating element shear sensor and method for fabricating the same are provided. According to an embodiment, a microelectromechanical systems (MEMS)-based capacitive floating element shear stress sensor is provided that can achieve time-resolved turbulence measurement. In one embodiment, a differential capacitive transduction scheme is used for shear stress measurement. The floating element structure for the differential capacitive transduction scheme incorporates inter digitated comb fingers forming differential capacitors, which provide electrical output proportional to the floating element deflection.

Abstract: A device for testing roller burnishing tools for a roller burnishing machine including at least one burnishing roller. The device includes a mechanism to hold and to drive in the roller burnishing machine, which causes the test device to rotate; a roller bearing raceway pressing against the roller, the roller bearing raceway exhibiting symmetry of revolution about the axis of rotation of the device, with a profile including a rounded portion; and a cylindrical rolling bearing raceway bearing against support wheels of the roller burnishing machine.

Abstract: A capacitive sensor (200) for a touch sensitive electronic device (800) includes at least one graphic (401) visible to a user. The graphic (401) is configured so as to be non-electrically interfering with the electrode array of the capacitive sensor (200). A substrate (101), configured to transmit light, has a layer of capacitive sensor material (201) deposited thereon. The layer of capacitive sensor material (201) is electrically conductive and pellucid. A layer of selectively disposed electrically conductive material (202) is then electrically coupled to the layer of capacitive sensor material (201). The layer of selectively disposed electrically conductive material (202) is arranged as a graphic, which may be a logo, brand, or other mark. The layer of selectively disposed electrically conductive material (202) has a reflectivity that is greater than the layer of capacitive sensor material (201) so as to make the graphic (401) visible to a user.

Abstract: A piezoelectric measuring element comprises at least one bar with transverse effect which can be used with two conductor technology. Poles comprising the metallizations, electrodes and lines in the measuring element are embodied with one or more piezoelectric bars with transverse effect such that the electric capacitances thereof with respect to the housing are identical. There can be a completely symmetrical design of the poles. A capacitor from one pole to the housing can correspond to the difference in capacitance of both poles to the environment.