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An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude (magnitude of the voltage or current) of a signal applied to its input ...
An operational amplifier (often op amp or opamp) is a DC-coupled electronic voltage amplifier with a differential input, a (usually) single-ended output, [1] and an extremely high gain. Its name comes from its original use of performing mathematical operations in analog computers .
"A mechanical amplifier is basically a mechanical resonator that resonates at the operating frequency and magnifies the amplitude of the vibration of the transducer at anti-node location." [ 6 ] Resonance is the physical phenomenon where the amplitude of oscillation (output) exhibit a buildup over time when the frequency of the external forcing ...
Such is the case with the operational transconductance amplifier, which has an open-loop gain (transconductance) in siemens , because the gain is a ratio of the output current to the input voltage. Example
There are a number of RF amplifier tubes that operate in a similar fashion to the TWT, known collectively as velocity-modulated tubes. The best known example is the klystron. All of these tubes use the same basic "bunching" of electrons to provide the amplification process, and differ largely in what process causes the velocity modulation to occur.
Present definition [ edit ] The 2019 revision of the SI defined the ampere by taking the fixed numerical value of the elementary charge e to be 1.602 176 634 × 10 −19 when expressed in the unit C, which is equal to A⋅s, where the second is defined in terms of ∆ ν Cs , the unperturbed ground state hyperfine transition frequency of the ...
In electronics, power amplifier classes are letter symbols applied to different power amplifier types. The class gives a broad indication of an amplifier 's characteristics and performance. The first three classes are related to the time period that the active amplifier device is passing current, expressed as a fraction of the period of a ...
In physics, a quantum amplifier is an amplifier that uses quantum mechanical methods to amplify a signal; examples include the active elements of lasers and optical amplifiers. The main properties of the quantum amplifier are its amplification coefficient and uncertainty .