Electronics Glossary – Q

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Term Definition
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.
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.