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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 and home theater worlds, a preamplifier accepts signals from audio and video sources and feeds them to the amplifier and screen. 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.