Abstract: A thermal conductivity measuring device includes a diaphragm portion, a thermal conductivity detector, a temperature sensor, a control section, and a thermal conductivity calculating section. The diaphragm portion is formed on a base. The thermal conductivity detector is formed in the diaphragm portion to perform conduction of heat to/from a sample gas. The temperature sensor is disposed on the base to be near the thermal conductivity detector so as to measure the ambient temperature around the base. The temperature sensor is thermally insulated from the thermal conductivity detector. The control section controls the amount of energy supplied to the thermal conductivity detector such that the temperature difference between the ambient temperature measured by the temperature sensor and the heating temperature of the thermal conductivity detector becomes a constant value.

Abstract: In a method of correcting temperature characteristics of a flow velocity sensor, the flow velocity sensor having a heater and a pair of temperature-measuring sensors arranged on both sides thereof is set such that the temperature-measuring sensors are located at upper and lower vertical positions along the flow of a target gas to be measured. A difference in self-heat amount is set between one of the temperature-measuring sensors, located on an upstream side of the flow of the gas, and the other temperature-measuring sensor located on a downstream side of the flow of the gas.

Abstract: A thermal conductivity detector includes a thin diaphragm, a heat-generating portion, and a pair of boundary holes. The thin diaphragm is obtained by forming a space in part of a base. The heat-generating portion is formed in the diaphragm. The boundary holes are formed to surround the heat-generating portion.

Abstract: A diaphragm-type sensor is disclosed which comprises a substrate including a cavity, a diaphragm formed on the cavity and supported by the substrate, a heater element arranged on the diaphragm, two sensor elements arranged on both sides of the heater means and slits between the heater means and the respective sensor means. The slits are effective in completely preventing the deformation of the diaphragm due to a heat propagated from the heater element, from influencing the sensor elements, whereby the diaphragm-type sensor exhibits stable output characteristics.