The Illustrated Dictionary of Electronics - Loscha

444 metronome • microcomponentmetronome A mechanical or electronic device thatproduces audible beats (ticks). It is commonlyused in setting the tempo for music, and for audiblytiming certain processes.MeV Abbreviation of MEGAELECTRONVOLT(s).MEW Abbreviation of MICROWAVE EARLY WARN-ING.mF Abbreviation of MILLIFARAD.MF 1. Abbreviation of MEDIUM FREQUENCY.2. Abbreviation of MIDFREQUENCY.MFD Abbreviation of MAGNETOFLUID DYNAMICS(see MAGNETOHYDRODYNAMICS).MFSK Abbreviation of MULTIPLE FREQUENCY-SHIFT KEYING.Mg Symbol for MAGNESIUM.mg Abbreviation of MILLIGRAM.MGD Abbreviation of MAGNETOGASDYNAMICS(see MAGNETOHYDRODYNAMICS).MHD Abbreviation of MAGNETOHYDRODYNAM-ICS.MHD generator See MAGNETOHYDRODYNAMICGENERATOR.MHD gyroscope See MAGNETOHYDRODYNAMICGYROSCOPE.MHD power generation See MAGNETOHYDRO-DYNAMIC GENERATOR.mho Obsolete term for the standard unit of electricalconductance. See SIEMENS.mhp Abbreviation of MILLIHORSEPOWER.MHz Abbreviation of MEGAHERTZ.mi Abbreviation of MILE. (Also, m.)MIC Abbreviation of MICROWAVE INTEGRATEDCIRCUIT.mic Abbreviation of MICROPHONE.mica A dielectric mineral of complex silicate composition,easily separated into numerous thin, transparentsheets. It is widely used as a capacitordielectric and high-temperature electrical insulator.Dielectric constant, 2.5 to 7. Dielectricstrength, 50 to 220 kV/mm. Also see MUSCOVITE.mica capacitor A component that is made by alternatelystacking metal sheets and layers of mica,or by applying silver ink to sheets of mica. Themetal sheets are wired together into two meshedsets, forming the two terminals of the capacitor.This type of capacitor is noted for low loss. Voltageratings can be up to several thousand volts ifthick sheets of mica are used. But these capacitorsare physically bulky in proportion to their capacitance.The main application is in radioreceivers and transmitters. Compare CERAMICCAPACITOR, ELECTROLYTIC CAPACITOR,PAPER CAPACITOR, PLASTIC-FILM CAPACITOR,TANTALUM CAPACITOR.MICR Abbreviation of MAGNETIC INK CHARAC-TER RECOGNITION.micro- 1. A prefix meaning MILLIONTH(S) (i.e.,10 –6 ). 2. A prefix meaning extremely small (as inmicrostructure). Compare MACRO-.microalloy diffused transistor Abbreviation,MADT. A MICROALLOY TRANSISTOR having aCoatingLeadsMetalelectrodesmica capacitorThin layerof micauniform base region that is diffused into thewafer before the emitter and collector electrodesare produced by alloying.microalloy transistor Abbreviation, MAT. A transistorhaving tiny emitter and collector electrodesthat are formed by alloying a thin film of impuritymaterial with a collector pit and emitter pit facingeach other on opposite surfaces of the semiconductorwafer. Also see SURFACE-BARRIERTRANSISTOR.microammeter A usually direct-reading instrumentused to measure current in the microampererange. Also see CURRENT METER.microampere A small unit of current, equal to 10 –6(0.000001) A.microbalance A sensitive electronic weighing device.One type uses one or more servo amplifiersfor the balancing operation.microbar A cgs unit of low pressure, equal to 10 –6b or 0.1 pascal. Also see BAR, 1 and MILLIBAR.microbarograph A barograph that is sensitive tosmall changes in pressure.microbeam An energy beam (ray) having extremelysmall cross section.microcircuit An extremely small circuit fabricatedupon and within a substrate, such as a semiconductorchip. Also see INTEGRATED CIRCUIT.microcode 1. See MICROINSTRUCTION. 2. A codefor MICROPROGRAMMING.microcomponent A tiny component in an electroniccircuit. Examples are the resistors, capacitors,diodes, and transistors fabricated onto anintegrated-circuit chip.