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preamplifier(pree-am -plă-fÿ-er) An amplifier used in a radio telescope to boost the signals from the antenna before they are fed to the receiver.
A voltage amplifier suitable for operation with a low-level input signal. It is intended to be connected to another amplifier with a higher input level. Preamplifiers are necessary when an audio amplifier is to be used with low-output transducers such as magnetic phonograph pickups. A preamplifier may incorporate frequency-correcting networks to compensate for the frequency characteristics of a given input transducer and to make the frequency response of the preamplifier-amplifier combination uniform. See Amplifier, Voltage amplifier
preamplifier(1) In the hi-fi stereo world, a preamplifier accepts signals from audio sources (CDs, turntables, etc.) and boosts the current to the level required for amplification. For details, see preamp.
(2) An electronic device that boosts signals to a certain level, which may be further amplified. Preamplifiers are used in fields such as test and measurement, optical detection and audio engineering.