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. |