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Internals of a pyroelectric sensor. Pyroelectricity (from Greek: pyr (πυρ), "fire" and electricity) is a property of certain crystals which are naturally electrically polarized and as a result contain large electric fields. [1] Pyroelectricity can be described as the ability of certain materials to generate a temporary voltage when they are ...
In terms of the pyroelectric detector, it can be used as a sensor to support the system. Due to the unipolar axis characteristics of the pyroelectric crystal, it is characterized by asymmetry. Polarization due to changes in temperature, the so-called pyroelectric effect, is currently widely used in sensor technology.
A piezoelectric sensor is a device that uses the piezoelectric effect to measure changes in pressure, acceleration, temperature, strain, or force by converting them to an electrical charge. The prefix piezo- is Greek for 'press' or 'squeeze'.
Thermopile laser sensors find their use mainly where sensitivity to a wide spectral range is needed or where high laser powers need to be measured. Thermopile sensors are integrated into laser systems and laser sources and are used for sporadic as well as continuous monitoring of laser power, e.g. in feedback control loops.
Golay cells follow thermal expansion. In IR spectrometers the pyroelectric detectors are the most widespread. The response time and sensitivity of photonic detectors can be much higher, but usually these have to be cooled to cut thermal noise. The materials in these are semiconductors with narrow band gaps. Incident IR photons can cause ...
In the tg + tg − conformation, the inclination of dipoles to the chain axis leads to the polar components of both perpendicular (4.0 × 10 −30 C-m per repeat) and parallel to the chain (3.4 × 10 −30 C-m per repeat). In the all trans structure, the alignment of all its dipoles are in the same direction normal to the chain axis.
The earliest example of a pyrometer thought to be in existence is the Hindley Pyrometer held by the London Science Museum, dating from 1752, produced for the Royal collection. The pyrometer was a well known enough instrument that it was described in some detail by the mathematician Euler in 1760.
The Olsen cycle can generate electricity directly from heat when applied to a pyroelectric material, [6] and has been the most favorable method for the generation of electricity from heat using pyroelectric energy harvesting. [7] It consists of two isothermal and two isoelectric field processes in the displacement versus electric field diagram. [8]