Electronics Glossary · Q

Electronics glossary — Letter Q

16 definitions of electronic component and semiconductor terms starting with Q. Part of the Hybrid Electronics glossary — an A–Z working reference for engineers and buyers.

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16 terms starting with Q

Q: Q factor – (1) Quality factor: the ratio of energy stored to energy dissipated. A measure of the relative losses in an inductor. It is also known as the quality factor, defined as the ratio of inductive reactance to effective resistance. Q is zero at the SRF of an inductor. (2) Also the symbol for electrical charge. (3) An omnipotent being in the Star Trek universe.
Q Factor: Ratio of energy stored to energy dissipated. A measure of the relative losses in an inductor. It is also known as the quality factor, defined as the ratio of inductive reactance to effective resistance. Q is zero at the SRF of an inductor.
QAM: Quadrature Amplitude Modulation. A two-dimensional modulation used for ADSL, cable modems and proposed for VDSL. CAP is a special case of QAM. In QAM, a single carrier frequency is modulated in both sine and cosine components.
QFN: Quad Flat No-lead – a small surface-mount package with contacts along all four edges of its underside and usually an exposed thermal pad. Widely used for analog, power and RF ICs.
QML: Qualified Manufacturers List – a Defense Logistics Agency list of manufacturers whose processes are certified to produce military-specification microcircuits or semiconductors, such as under MIL-PRF-38535 and MIL-PRF-19500.
QPL: Qualified Products List – a list of specific products that have been tested and approved as meeting a military specification.
QPSK: Quadrature phase shift key modulation.
Quadrature: Orthogonal.
Quality Assurance: Systematic, planned, and documented activities designed to provide confidence that a product will meet specifications.
Quality Control: Activities that monitor, measure, and control the characteristics of a material, component, or product to documented specifications.
quantizer: An analog-to-digital converter. A device that measures the magnitude of a time varying quantity in multiples of some fixed unit or quantum, at a specified instant or specified repetition rate, and delivers a proportional response that is usually in pulse code or digital form. The amplitude of the response signal is at each instant proportional to the number of quanta measured.
Quantum efficiency: In a photodiode, the ratio of primary carriers (electron-hole pairs) created to incident photons. A quantum efficiency of 70% means 7 out of 10 incident photons create a carrier.
queue: Waiting lines resulting from temporary delays in providing service.
Quick Disconnect: A type of connector shell that permits rapid locking and unlocking of two connector halves.
quiescent operating point: The dc voltages, currents, and dissipation associated with a circuit while it is not being subjected to an input signal.
QUIP: QUad In-line Package. A packaging technique similar to a DIP but having two rows of pins along each long side, or a total of four rows.