amplifier, device that accepts a varying input signal and produces an output signal that varies in the same way as the input but has a larger amplitude. The input signal may be a current, a voltage, a mechanical motion, or any other signal; the output signal is usually of the same nature. The most common types of amplifiers are electronic and have transistors transistor, three-terminal, solid-state electronic device used for amplification and switching. It is the solid-state analog to the triode electron tube ; the transistor has replaced the electron tube for virtually all common applications.
..... Click the link for more information. or electron tubes electron tube, device consisting of a sealed enclosure in which electrons flow between electrodes separated either by a vacuum (in a vacuum tube) or by an ionized gas at low pressure (in a gas tube).
..... Click the link for more information. as their principal components. Electronic amplifiers are used in radio and television transmitters and receivers, audio and stereo systems, intercoms, and other consumer electronics devices. Amplifiers in their simplest form are built around a single transistor. In one type of single-transistor amplifier, known as a common-emitter circuit, a varying input voltage is fed to the base of the transistor, and the output appears at the transistor's collector; the ratio of the output voltage to the input voltage is called the voltage gain. For many purposes a single transistor does not provide sufficient gain, or amplification. In a cascade, or multistage, amplifier, the output of the first amplifying device (transistor) is fed as input to the second amplifying device, whose output is fed as input to the third, and so on until an adequate signal amplification has been achieved. In a device such as a radio receiver, several amplifiers boost a weak input signal until it is powerful enough to drive a speaker. Usually, multistage amplifiers are not made of discrete components, but are built as integrated circuits integrated circuit (IC), electronic circuit built on a semiconductor substrate, usually one of single-crystal silicon. The circuit, often called a chip, is packaged in a hermetically sealed case or a nonhermetic plastic capsule, with leads extending from it for
..... Click the link for more information. . Another less common group of electronic amplifiers use magnetic devices as their principal components. There are also many kinds of mechanical amplifiers, e.g., the power steering system of an automobile. See operational amplifier operational amplifier, amplifier whose output voltage is proportional to the negative of its input voltage and that boosts the amplitude of an input signal many times, i.e., has a very high gain.
..... Click the link for more information. .

amplifier

Device that responds to a small input signal (voltage, current, or power) and delivers a larger output signal with the same waveform features. Amplifiers are used in radio and television receivers, high-fidelity audio equipment, and computers. Amplification can be provided by electromechanical devices (e.g., transformers and generators) and vacuum tubes, but most electronic systems now employ solid-state microcircuits. One amplifier is usually insufficient, so its output is fed into a second, whose output is fed to a third, and so on, until the output level is satisfactory.

A device that accepts a small signal and outputs a larger signal that generally matches the waveform characteristics of the input. Amplifiers are available to boost electrical and optical signals. See amplifier classes, Class D amplifier and PWM.

amplifier (redirected from Signal amplifier)

amplifier

amplifier
(redirected from Signal amplifier)