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THE OPERATIONAL AMPLIFIER(OP-AMP), An Operational Amplifies (op- Amp) is a direct-coupled high-gain, amplifies usually consisting of one or, and usually followed by a'level translator (i.e, emitter followes), and an output stage. The out put stage is generally a push-pull, 01. complementarysymmetry push-pull amplifier., An Operational amplifier is available as a, circuit (1C) package., The operational'amplifier is a veisatile device that can be, used to amplify de as well as ac input signals. In addition to, am plification it can perform mathematical operations süch as addition,, subtiaction, multiplication and integrat ion; thus it is Known as, operational ´amplifier (op-Amp)., With the addition of sitable exteinal feedback components,, the op-Amp can be used for a variety of applications, such as, active filters, ascillators, comporotors,egulators etc., Block Diapram Representation of op-Amp, since an op-amp is a multistage, amplities, it can be represented, by a block diagiam as shown in fig- 1., Non ivesting, Input,, more differential amplifiers, single integrated, Input, Stoge, Irventing, Intermediate, Stage, Level, shitting, Stage, output, Stage, ty, Sgmplementary, Symimetry, půsh-putl, ámplifier.., Inpit, Dual- input, balanced-output Unbalanced output folbwes ising, differential, amplifies, ·Dual-Input, Emitter-, differential, amplifier, pput, constant cunent, SOUIce., Stage, is lhe dual-input, balanced-ou&pukigstiffejential amplifier., This stoge generaly provides mast of ka voHageain f, Ihe amplifies, and also establishes the input resistance of Mha op-amp:, The intemediat e stage is usually another diffeiential amplifier,, which is driven by the output of he first staye. In, most, amplifiers the intermediate stage is dual input, umbalanced (single-, ended) out put., Because direct coupling is used, h de voltage at hē output, at Ihe output of he intesmediate stage is well above, potentíal. Therefore, generally, Ihe levell translator (shifting), gound

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Circuit is used after the intermediate stae to shift Ihē dc, level at Ihe output of Ihe intermediate, volts with sespect to ground-, stage downwand to zero, The final stoge is usually a push-pull complementary, amplifier output stage. The output, voltage swing and ráikes the curent supplying capability of Ihe, of- amp. A well- designed output stage provides lou output, resistance., stage, increases the output