The Illustrated Dictionary of Electronics - Loscha

446 micromodule • microsyncan be discrete, can consist of integrated circuits,or can be a combination of both. The module iseasily removed and replaced by means of a pluginsocket.micron See MICROMETER.microphone A transducer that converts soundwaves, especially speech and music, into electricalvoltage analogs.microphone amplifier A sensitive, low-distortion,low-noise amplifier used in voice wireless transmittersand public address systems. Most amplifiersof this type have a tailored frequencyresponse, passing audio between about 300 Hznd 3000 Hz, and attenuating audio outside this arange. The range 300 Hz to 3000 Hz is sufficientto convey intelligible voice signals, and also allowsfor audio-frequency-shift keying (AFSK) andslow-scan television (SSTV) audio input.Mic.+12 Vmicrophone amplifierOutputmicrophone boom A device used to hang a microphone,with the base out of the way. It is oftenused in radio broadcasting.microphone hummer See HUMMER.microphone input In an audio amplifier, a jack orother receptacle provided for connection to an externalmicrophone. It can also be used with otherlow-level audio apparatus. The jack is connectedto a MICROPHONE AMPLIFIER that provideshigh gain with minimum internal noise.microphone oscillator See HUMMER.microphonics Ringing (electrical noises) set up bythe vibration of a component having loose or movableelements. For example, ringing noises aregenerated in some circuit boards when they receivea physical blow.microphonograph A recorder of very low-intensitysound.microphonoscope An electronic stethoscope, usingamplification to enhance the response.microphotograph An extremely small photograph,often of a pattern or mask used in producingtransistors and integrated circuits. Not to be confusedwith photomicrograph, a photograph takenthrough a microscope.microphotometer A sensitive instrument for measuringsmall-area light intensity.microphysics The branch of physics concernedwith atoms, molecules, and subatomic particles.micropower Extremely small amounts of power—especially the very low direct-current supplypower required by some transistors.microprocessor The integrated circuit (IC), alsoknown as a chip, that coordinates the actions of acomputer and does the calculations. It is locatedon the motherboard (sometimes called the logicboard). These devices get more powerful everyyear. Physically, this translates to an increasingnumber of digital switching transistors per chip.The number of digital switches that can be fabricatedonto a semiconductor chip of a particularsize is ultimately limited by the structure of matter.Compare MICROCOMPUTER.microprogram 1. In computer operations, a routineof microinstructions that provides a computera specific function, independent of thoseestablished by programs being run or by themonitor program. Also see MICROINSTRUCTION.2. In the direction of a computer, use of a routinethat is stored specifically in the memory, insteadof elsewhere.microprogramming In the direction of a computer,the use of a routine that is stored specificallyin the memory, instead of elsewhere.micropulsation Also called micropulse. A pulse ofextremely short duration.microradiometer A sensitive detector of heat andinfrared radiation, consisting essentially of athermopile carried by the moving coil of a galvanometer.microrutherford A unit of radioactivity equal toone disintegration per second or 10 –6 (0.000001)rutherford. Also see RUTHERFORD.microsecond A unit of time measure equal to 10 –6(0.000001) second.microsiemens A unit of conductance equal to 10 –6(0.000001) siemens.microspectrophotometer An extremely sensitivespectrophotometer for examining light from tinyareas.microstrip A microwave component that is, in effect,a single-wire transmission line operatingabove ground.microsyn A device that translates rotational positioninto an electrical signal. Similar to aSELSYN. It is used for such purposes as rotatordirectionreading.