Abstract: A low cost, bi-directional manifold air flow sensing device based on sensed temperature differential due to airflow achieves improved sensitivity and frequency response by eliminating the heater element of the conventional sensor topology, and operating the sensor elements at a relatively higher current so that each temperature sensing element heats both itself and the other temperature sensing element. The sensitivity is significantly increased due to the increased current in the sensor elements, and the frequency response is significantly increased due to closer spacing of the sensor elements. With this new topology, the sensor elements are said to be mutually heated. In a particularly advantageous mechanization, the sensing device includes two separate pairs of upstream and downstream sensing elements, and the sensing elements are connected in the four legs of a Wheatstone bridge.

Abstract: A temperature sensor apparatus comprising: a capacitor with first and second conductors and a dielectric material between the conductors; a frequency generator coupled to the capacitor and providing an excitation signal thereto; a processor coupled to the capacitor, wherein the processor monitors a capacitance of the capacitor, converts the capacitance to a temperature signal, and alters a frequency of the excitation signal when the temperature signal passes a predetermined threshold.

Abstract: A temperature sensor comprising: a wave guide with a cylindrical wall; a material of low emissivity included at the cylindrical wall for generating black body radiation into the wave guide, wherein at least a portion of the generated black body radiation is carried through the wave guide; a first sensor receiving the generated black body radiation and providing a first output signal indicative of a first magnitude of a first bandwidth of the generated black body radiation; and a second sensor receiving the generated black body radiation and providing a second output signal indicative of a second magnitude of a second bandwidth of the generated black body radiation, wherein a difference between the first and second output signals is a linearized indication of temperature of at least a portion of the wave guide.