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TRIAC. For other uses, see Triac. A TRIAC (triode for alternating current; also bidirectional triode thyristor or bilateral triode thyristor[ 1 ]) is a three-terminal electronic component that conducts current in either direction when triggered. The term TRIAC is a genericised trademark. TRIACs are a subset of thyristors (analogous to a relay ...
In optical mineralogy, an interference colour chart, also known as the Michel-Levy chart, is a tool first developed by Auguste Michel-Lévy to identify minerals in thin section using a petrographic microscope. With a known thickness of the thin section, minerals have specific and predictable colours in cross- polarized light, and this chart can ...
The thyristor is a four-layered, three-terminal semiconductor device, with each layer consisting of alternating N-type or P-type material, for example P-N-P-N. The main terminals, labelled anode and cathode, are across all four layers. The control terminal, called the gate, is attached to p-type material near the cathode.
Köhler illumination is a method of specimen illumination used for transmitted and reflected light (trans- and epi-illuminated) optical microscopy. Köhler illumination acts to generate an even illumination of the sample and ensures that an image of the illumination source (for example a halogen lamp filament) is not visible in the resulting image.
Polarized light microscopy. Polarized light microscopy can mean any of a number of optical microscopy techniques involving polarized light. Simple techniques include illumination of the sample with polarized light. Directly transmitted light can, optionally, be blocked with a polariser oriented at 90 degrees to the illumination.
A condenser (right) and its respective diaphragm (left) A condenser is an optical lens that renders a divergent light beam from a point light source into a parallel or converging beam to illuminate an object to be imaged. Condensers are an essential part of any imaging device, such as microscopes, enlargers, slide projectors, and telescopes.
Above: White light Interferogram, Below: Red-, Green- and Blue channels of the White light interferogram shown above. As described here, white light interferometry is a non-contact optical method for surface height measurement on 3D structures with surface profiles varying between tens of nanometers and a few centimeters.
Phase-contrast imaging is a method of imaging that has a range of different applications. It measures differences in the refractive index of different materials to differentiate between structures under analysis. In conventional light microscopy, phase contrast can be employed to distinguish between structures of similar transparency, and to ...