The Illustrated Dictionary of Electronics - Loscha

unidirectional speaker • unilateral field-effect transistor 709270°0°180°unidirectional pattern90°unidirectional speaker See UNIDIRECTIONALLOUDSPEAKER.unidirectional transducer A transducer that operatesin one direction only (i.e., its input andoutput cannot be interchanged).unidirectional voltage A voltage that never changespolarity, although it might fluctuate in value.UNIFET Abbreviation of UNIPOLAR FIELD-EFFECT TRANSISTOR. (Also, UFET.)unified-field theory A theory, as yet unproved,that all forces in nature are interrelated and arecontrolled by the same causes and factors. AlbertEinstein worked on this theory after he successfullydeveloped the theories of relativity.unifilar Having (or wound as) one fiber, wire, filament,or thread.unifilar magnetometer A magnetometer in whicha bar is suspended at its center of gravity by asingle thread.unifilar suspension A method of meter constructionin which the moving part is suspended by asingle filament. The torque might be provided bythis filament or by a spring or other resisting device;the greater the displacement, the greater thetorque.uniform circular motion Motion at a uniform rateand describing a circle (e.g., a motor armature rotatingat a constant speed).uniform electric field An electric field in which allthe lines of flux are straight and parallel, and inwhich the electrostatic force has the same valueat all points (e.g., the field between two oppositelycharged, flat, parallel plates).uniform field See UNIFORM ELECTRIC FIELDand UNIFORM MAGNETIC FIELD.uniform frequency response Frequency responsethat is flat throughout a specified range. Such responseis characterized by the transmission of asignal with no introduced amplitude or phasedistortion.uniform line A transmission line having identicalelectrical properties over its entire length.uniform magnetic field A magnetic field in whichall the lines of flux are straight and parallel, andin which the magnetic force has the same value atall points.uniform plane wave A free-space plane wave at aninfinite distance from the generator, having constant-amplitudeelectric and magnetic field vectorsover the equiphase surfaces.uniform precession In regions of the uniformmagnetic field of a sample of material, the state inwhich the magnetic moments of all atoms areparallel and precess in phase around the magneticfield.uniform waveguide A waveguide having constantelectrical and physical characteristics along itsaxis.uniground 1. The grounding of a circuit at onepoint to reduce susceptibility to hum and noise.2. The point at which such a connection is made.unijunction transistor A semiconductor deviceconsisting of a thin silicon bar on which a singlepn junction acting as an emitter is formed nearone end. Two bases are provided—each an ohmicconnection made to one end of the bar. Alsocalled double-base diode.PictorialBase 1nBase 2pBase 1Base 2EmitterSymbolunijunction transistorEmitterunilateral area track A film sound track havingmodulation on only one edge of the opaque area.unilateral bearing In radio direction finding, abearing obtained with a finder that produces unilateralresponse and thereby eliminates 180-degree error.unilateral conductivity See UNIDIRECTIONALCONDUCTIVITY.unilateral element See UNIDIRECTIONALELEMENTS.unilateral field-effect transistor A field-effecttransistor whose source and drain terminals cannotbe interchanged. Also called ASYMMETRICALFIELD-EFFECT TRANSISTOR. Compare SYM-METRICAL FIELD-EFFECT TRANSISTOR.