A sensor element includes: an element base made of an oxygen-ion conductive solid electrolyte; an internal space provided inside the element base; an electrochemical pump cell configured to pump oxygen in and out between the internal space and outside; a porous thermal shock resistant layer provided to an outermost peripheral part in a predetermined range at one end part of the element base, at which a gas inlet is provided; and a buffer layer adjacent to the thermal shock resistant layer on a pump surface and a heater surface. A thermal diffusion time in a thickness direction of the thermal shock resistant layer is 0.4 sec to 1.0 sec inclusive, and a total thermal diffusion time in a stacking direction of the thermal shock resistant layer and the buffer layer is 0.2 sec to 1.0 sec inclusive.

A sensor element includes: an element base made of an oxygen-ion conductive solid electrolyte; an internal space provided inside the element base; an electrochemical pump cell configured to pump oxygen in and out between the internal space and outside; a porous thermal shock resistant layer provided to an outermost peripheral part in a predetermined range at one end part of the element base, at which a gas inlet is provided; and a buffer layer adjacent to the thermal shock resistant layer on a pump surface and a heater surface. A thermal diffusion time in a thickness direction of the thermal shock resistant layer is 0.4 sec to 1.0 sec inclusive, and a total thermal diffusion time in a stacking direction of the thermal shock resistant layer and the buffer layer is 0.2 sec to 1.0 sec inclusive.

A sensor element includes an element base made of an oxygen-ion conductive solid electrolyte, an internal space provided inside the element base, an electrochemical pump cell that pumps oxygen in and out between the internal space and outside, and a porous thermal shock resistant layer provided to an outermost peripheral part in a predetermined range at one end part of the element base, at which a gas inlet is provided. A thermal diffusion time in a thickness direction of the thermal shock resistant layer is 0.4 sec to 1.0 sec inclusive. A thermal diffusion time at a leading end part of the thermal shock resistant layer covering the gas inlet at a farthest leading end position at the one end part is longest, and a thermal diffusion time at a pump surface is longer than a thermal diffusion time at a heater surface.

A sensor element includes an element base made of an oxygen-ion conductive solid electrolyte, an internal space provided inside the element base, an electrochemical pump cell that pumps oxygen in and out between the internal space and outside, and a porous thermal shock resistant layer provided to an outermost peripheral part in a predetermined range at one end part of the element base, at which a gas inlet is provided. A thermal diffusion time in a thickness direction of the thermal shock resistant layer is 0.4 sec to 1.0 sec inclusive. A thermal diffusion time at a leading end part of the thermal shock resistant layer covering the gas inlet at a farthest leading end position at the one end part is longest, and a thermal diffusion time at a pump surface is longer than a thermal diffusion time at a heater surface.

Provided are: an electrode for a gas sensor formed as a porous electrode so as to stably allow reduction in electrode resistance for excellent low-temperature activity; and a gas sensor. The electrode (108, 110) for the gas sensor is adapted for use on a surface of a solid electrolyte body (109), which is predominantly formed of zirconia, and contains particles (2) of a noble metal or an alloy thereof, first ceramic particles (4) of stabilized zirconia or partially stabilized zirconia and second ceramic particles (6) of one or more selected from the group consisting of Al.sub.2O.sub.3, MgO, La.sub.2O.sub.3, spinel, zircon, mullite and cordierite, wherein the second ceramic particles are contained in an amount smaller than that of the first ceramic particles.

Provided are: an electrode for a gas sensor formed as a porous electrode so as to stably allow reduction in electrode resistance for excellent low-temperature activity; and a gas sensor. The electrode (108, 110) for the gas sensor is adapted for use on a surface of a solid electrolyte body (109), which is predominantly formed of zirconia, and contains particles (2) of a noble metal or an alloy thereof, first ceramic particles (4) of stabilized zirconia or partially stabilized zirconia and second ceramic particles (6) of one or more selected from the group consisting of Al.sub.2O.sub.3, MgO, La.sub.2O.sub.3, spinel, zircon, mullite and cordierite, wherein the second ceramic particles are contained in an amount smaller than that of the first ceramic particles.

Example devices and methods for compensating for monitoring a surge protection device are provided. In some embodiments, a device is configured to couple to a surge protection device. The device comprises a processor that is capable of sending a DC current signal. A serial data interface is electrically connected to the processor and includes at least one shift register. The device also comprises a multiplexer coupled to the serial data interface. The serial data interface is operable to direct the DC current through the multiplexer. The device also comprises an analog to digital converter (optionally embedded within the processor) that is operable to output a digital signal corresponding to a voltage induced by the DC current signal. Returned DC signals represent surge protection device's health and a multitude of other surge module information.

A gas sensor includes a detection circuit unit that detects a specific gas component in measured gas based on output from a sensor element. The detection circuit unit includes an AC voltage application unit that applies an AC voltage signal to a pair of electrode units in an electrochemical cell, a gas concentration detection unit that detects concentration information on the specific gas component from a DC signal component included in an output signal provided by the electrochemical cell, and a cell temperature detection unit that detects temperature information on the electrochemical cell from an AC signal component included in the output signal. The cell temperature detection unit includes a signal extraction unit that removes the DC signal component to separate the AC signal component from the output signal, and a synchronous detection unit that performs synchronous detection on the separated AC signal component using the AC voltage signal.

A gas sensor includes a detection circuit unit that detects a specific gas component in measured gas based on output from a sensor element. The detection circuit unit includes an AC voltage application unit that applies an AC voltage signal to a pair of electrode units in an electrochemical cell, a gas concentration detection unit that detects concentration information on the specific gas component from a DC signal component included in an output signal provided by the electrochemical cell, and a cell temperature detection unit that detects temperature information on the electrochemical cell from an AC signal component included in the output signal. The cell temperature detection unit includes a signal extraction unit that removes the DC signal component to separate the AC signal component from the output signal, and a synchronous detection unit that performs synchronous detection on the separated AC signal component using the AC voltage signal.

A sensor element includes: an element base including: a ceramic body made of an oxygen-ion conductive solid electrolyte, and having an inlet at one end portion thereof; at least one internal chamber located inside the ceramic body, and communicating with the gas inlet; and an electrochemical pump cell including an outer electrode, an inner electrode facing the chamber, and a solid electrolyte therebetween, and a porous leading-end protective layer covering a leading end surface and four side surfaces in a predetermined range of the element base on the one end portion, wherein the protective layer has an extension extending into the gas inlet and fixed to an inner wall surface of the ceramic body demarcating the gas inlet, and a gap communicating with the gas inlet is located in the protective layer, with demarcated by a portion of the protective layer continuous with the extension.