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 divided based on their conduction model. Negative Temperature Coefficient (NTC) thermistors have less resistance at higher temperatures, while Positive Temperature Coefficient (PTC) thermistors have more resistance at higher temperatures.
NTC thermistor are widely used as inrush current limiters, temperature sensors, while PTC thermistors are used as self-resetting overcurrent protectors, and self-regulating heating elements. An operational temperature range of a thermistor is dependent on the probe type and is typically between −100 °C and 300 °C (−148 °F and 572 °F).
Depending on materials used, thermistors are classified into two types:
With NTC thermistors, resistance decreases as temperature rises; usually due to an increase in conduction electrons bumped up by thermal agitation from the valence band. An NTC is commonly used as a temperature sensor, or in series with a circuit as an inrush current limiter.
With PTC thermistors, resistance increases as temperature rises; usually due to increased thermal lattice agitations particularly those of impurities and imperfections. PTC thermistors are commonly installed in series with a circuit, and used to protect against overcurrent conditions, as resettable fuses.
Thermistors are generally produced using powdered metal oxides. With vastly improved formulas and techniques over the past 20 years, NTC thermistors can now achieve accuracies over wide temperature ranges such as ±0.1 °C or ±0.2 °C from 0 °C to 70 °C with excellent long-term stability. NTC thermistor elements come in many styles such as axial-leaded glass-encapsulated (DO-35, DO-34 and DO-41 diodes), glass-coated chips, epoxy-coated with bare or insulated lead wire and surface-mount, as well as thin film versions.
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Fundamental principles and methods used for physiological signal conditioning. Electrode, optical, resistive, capacitive, inductive, and piezoelectric sensor techniques used to detect and convert phys
Students learn about response of electrically insulating materials to electrical and mechanical fields. The emphasis is on effect of various types of defects on properties, on crystal structure/micros
Electrical resistivity (also called volume resistivity or specific electrical resistance) is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. A low resistivity indicates a material that readily allows electric current. Resistivity is commonly represented by the Greek letter ρ (rho). The SI unit of electrical resistivity is the ohm-metre (Ω⋅m).
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with mechanical friction. The SI unit of electrical resistance is the ohm (Ω), while electrical conductance is measured in siemens (S) (formerly called the 'mho' and then represented by ℧). The resistance of an object depends in large part on the material it is made of.
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. Thermocouples are widely used as temperature sensors. Commercial thermocouples are inexpensive, interchangeable, are supplied with standard connectors, and can measure a wide range of temperatures.
Explores metal resistance temperature sensors, voltage dividers, and thermistors' characteristics, calibration, and applications.
Covers signal conditioners for resistive and capacitive sensors, including measurement methods, voltage dividers, Wheatstone bridges, and sensor interfaces.
Covers Thevenin and Norton theorems for simplifying complex circuits into equivalent ones.
In Atomic force microscopy (AFM), the tip-sample interaction force can be measured
through two primary detection techniques: optical beam detection (OBD) and electrical (self-sensing)
readout. Compared to the optical method, the convenience of the self-sen ...
EPFL2019
The drift of temperature measurements by semiconductor negative temperature coefficient thermistors is a well-known problem. This study analyzes the drift characteristics of the thermistors designed and used at the Royal Netherlands Institute for Sea Resea ...
Turbidity currents emanating from the Rhône River into Lake Geneva were first inferred by François-Alphonse Forel in the nineteenth century. This site remains attractive for several reasons. (1) Permanent measuring stations on the Rhône and Lake Geneva pro ...