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Differential amplifier - Definition and Overview |
| Related Words: Accurate, Algorithmic, Aroma, Attribute, Badge, Brand, Cachet, Cardinal, Cast, Character, Characteristic, Classificatory, Cogwheel, Configuration, Critical, Cut, Decimal |
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A differential amplifier is a type of electronic amplifier that multiplies the difference between two inputs by some constant factor (the gain). A common form of differential amplifier is the operational amplifier, or op-amp. Given two inputs A and B, a perfect differential amplifier gives an output O:
<math>O = K(A - B)<math>
where K is the gain.
Note that a differential amplifier is a more general form of amplifier than one with a single input; by grounding one input of a differential amplifier, a single-ended amplifier results.
Differential amplifiers are found in any system that utilises negative feedback, where one input is used for the input signal, the other for the feedback signal. A common application is for the control of motors or servos, as well as for signal amplification applications. In discrete electronics, a common arrangement for implementing a differential amplifier is the long-tailed pair, which is also usually found as the differential element in most op-amp integrated circuits.
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