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A thermistor is a semiconductor type of resistor whose resistance is strongly dependent on temperature, more so than in standard resistors. The word thermistor is a portmanteau of thermal and resistor. Thermistors are categorized based on their conduction models. Negative-temperature-coefficient (NTC) thermistors have less resistance at higher ...
A special form of the Pirani gauge is the pulsed Pirani vacuum gauge where the sensor wire is not operated at a constant temperature, but is cyclically heated up to a certain temperature threshold by an increasing voltage ramp. When the threshold is reached, the heating voltage is switched off and the sensor cools down again.
Bolometer. Spiderweb bolometer for measurements of the cosmic microwave background radiation. Image credit: NASA/JPL-Caltech. A bolometer is a device for measuring radiant heat by means of a material having a temperature-dependent electrical resistance. [1][2] It was invented in 1878 by the American astronomer Samuel Pierpont Langley.
Resistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature. Many RTD elements consist of a length of fine wire wrapped around a heat-resistant ceramic or glass core but other constructions are also used. The RTD wire is a pure material, typically platinum (Pt), nickel (Ni), or copper (Cu).
The Steinhart–Hart equation is a model relating the varying electrical resistance of a semiconductor to its varying temperatures. The equation is. where. are the Steinhart–Hart coefficients, which are characteristics specific to the bulk semiconductor material over a given temperature range of interest.
Thermocouple. A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of the Seebeck effect, and this voltage can be interpreted to measure temperature.
The silicon bandgap temperature sensor is an extremely common form of temperature sensor (thermometer) used in electronic equipment. Its main advantage is that it can be included in a silicon integrated circuit at very low cost. The principle of the sensor is that the forward voltage of a silicon diode, which may be the base-emitter junction of ...
Electronic thermostats, instead, use a thermistor or other semiconductor sensor, processing temperature change as electronic signals, to control the heating or cooling equipment. Conventional thermostats are example of " bang-bang controllers " as the controlled system either operates at full capacity once the setpoint is reached, or keeps ...