A biosensor for measuring an electrical response from a biological sample. The biosensor includes a substrate, a passivation layer grown on a surface of the substrate, a patterned catalyst layer deposited on the passivation layer, and three electrodes grown on the patterned catalyst layer. The three electrodes include a working electrode, a counter electrode, and a reference electrode. The working electrode includes a first array of electrically conductive biocompatible nanostructures that is configured to be an attachment site for the biological sample. The counter electrode includes a second array of electrically conductive biocompatible nanostructures that is configured to acquire the electrical response from the working electrode. The reference electrode includes a third array of electrically conductive biocompatible nanostructures that is configured to adjust a specific voltage around the working and the counter electrodes.

A sensor element includes an element body including an oxygen-ion-conductive solid electrolyte layer, the element body having a longitudinal direction, a measurement electrode disposed in the element body, a reference electrode disposed in the element body so as to come into contact with a reference gas, and a heater configured to heat the solid electrolyte layer. A center of gravity of the reference electrode overlaps the measurement electrode as viewed in a thickness direction of the solid electrolyte layer. A length of each of the reference electrode and the measurement electrode in a front-rear direction is less than or equal to 1.1 mm, the front-rear direction being a direction along the longitudinal direction of the element body. An area of the reference electrode as viewed in the thickness direction is greater than or equal to 1.0 mm.sup.2.

A solid electrolyte three-electrode electrochemical test device comprises a housing, a working electrode, a counter electrode, a reference electrode, a first conductive structure, a second conductive structure, a third conductive structure, and a solid electrolyte layer. The housing comprises a groove and a first through hole located at a bottom of the groove. The reference electrode is insulated from the counter electrode. The first conductive structure and the working electrode are stacked with each other, and the working electrode and at least a part of the first conductive structure are located in the first through hole. The solid electrolyte layer, the counter electrode, the reference electrode, the second conductive structure and the third conductive structure are located in the groove, and the first conductive structure, the working electrode, the solid electrolyte layer, the counter electrode, and the second conductive structure are sequentially stacked and located coaxially with each other.

A solid electrolyte three-electrode electrochemical test device comprises a housing, a working electrode, a counter electrode, a reference electrode, a first conductive structure, a second conductive structure, a third conductive structure, and a solid electrolyte layer. The housing comprises a groove and a first through hole located at a bottom of the groove. The reference electrode is insulated from the counter electrode. The first conductive structure and the working electrode are stacked with each other, and the working electrode and at least a part of the first conductive structure are located in the first through hole. The solid electrolyte layer, the counter electrode, the reference electrode, the second conductive structure and the third conductive structure are located in the groove, and the first conductive structure, the working electrode, the solid electrolyte layer, the counter electrode, and the second conductive structure are sequentially stacked and located coaxially with each other.

A limiting current-type gas sensor element including a plurality of stacked ceramic layers and configured to output a limiting current value which depends on a concentration of a specific gas in a gas to be measured when a certain voltage is applied. The gas sensor element includes a solid electrolyte member having oxygen ion conductivity; a heater that heats the solid electrolyte member; a measurement electrode and a reference electrode provided on the solid electrolyte member; a chamber facing the measurement electrode and into which the gas to be measured is introduced; a gas inlet located to a tip side of the chamber in a longitudinal direction; and a diffusion resistance part provided in the gas inlet. A heating center of the heater is located further to the tip side than an electrode center of the measurement electrode is.

Methods and apparatus for sensing hydrogen in a mixture of hydrogen and natural gas are provided. One example of the apparatus comprises: a first chamber for receiving air; a second chamber for receiving the mixture of hydrogen and natural gas; a first electrode for adsorbing oxygen molecules from air in the first chamber and for reducing the oxygen molecules to oxide ions; a second electrode; an ionic conductor for transporting the oxide ions from the first electrode to the second electrode in order to cause the transported oxide ions to combine with hydrogen molecules at the second electrode; sensing circuitry for sensing an electrical parameter associated with the combination of the transported oxide ions with the hydrogen molecules at the second electrode; and processing circuitry configured to determine a proportion of hydrogen in the mixture, based at least in part on the electrical parameter sensed by the sensing circuitry.

A gas sensor includes: a substrate; an insulating layer arranged over the substrate; and a solid electrolyte layer, wherein the substrate is formed with a cavity that penetrates the substrate in a thickness direction of the substrate, wherein the insulating layer has a peripheral portion arranged over the substrate around the cavity, and a membrane portion which is located over the cavity and is connected to the peripheral portion, wherein the membrane portion includes a movable portion, wherein a through-hole, which penetrates the membrane portion around the movable portion in the thickness direction, is formed such that the movable portion is capable of being displaced along the thickness direction, and wherein the solid electrolyte layer is arranged over the movable portion.

A laminated gas sensor element is provided by laminating a plurality of ceramic layers. The gas sensor element includes: a solid electrolyte body having oxygen ion conductivity; a measurement electrode provided on a first principal surface of the solid electrolyte body; a reference electrode provided on a second principal surface of the solid electrolyte body; a chamber facing the measurement electrode and into which a measured gas is introduced; and a heater heating the solid electrolyte body. The chamber comprises at least one projecting corner portion, the at least one projecting corner portion projecting, on a cross section perpendicular to a longitudinal direction of the gas sensor element, in a width direction perpendicular to both of the longitudinal direction and a laminating direction. A tip of the projecting corner portion is disposed on a side closer to the heater than a center of the chamber in the laminating direction is.

A gas sensor has a sensor element, first element pads, second element pads, first contact-point members, and second contact-point members. The sensor element has first and second surfaces that are positioned on opposite sides in a first direction. The first element pads are disposed on the first surface. The second element pads are disposed on the second surface in a quantity greater than that of the first element pads. The first and second contact-point members are connected to the first and second element pads, respectively. The width (Wt) of at least one of the second contact-point members is less than the widths (Wa-Wd) of the rest of the first and second contact-point members.

A handheld portable oxygen monitor for monitoring oxygen includes one or more of (1) a replaceable dust filter element removably disposed in a gas inlet pathway extending from an gas inlet port to an oxygen sensor, (2) an oxygen sensor module including the oxygen sensor and a circuit board on which the oxygen sensor is mounted, the oxygen sensor module being removably mounted to a circuit board holder, (3) configurable gas pathway components within the oxygen monitor housing, and (4) a controller operable to enable a remote device to (a) control one or more operations of the oxygen monitor, (b) receive real-time oxygen monitoring data from the oxygen monitor for display on the remote device, (c) upload logging event data from the oxygen monitor storage, (d) obtain system information from the oxygen monitor storage, and (e) perform firmware updates on the oxygen monitor to modify its programming.