Amplifier An amplifier electronic amplifier or informally amp

Amplifier An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the power of a signal (a time-varying voltage or current). An amplifier uses electric power from a power supply to increase the amplitude of a signal. The amount of amplification provided by an amplifier is measured by its gain: the ratio of output to input. An amplifier is a circuit that can give a power gain greater than one Amplifier is the generic term used to describe a circuit which increases its input signal, but not all amplifiers are the same as they are classified according to their circuit configurations and methods of operation. input output Dependent source Amplifier type Gain units Unitless I I Current controlled current source Current amplifier I V Current controlled voltage source Transresistance amplifier V I Voltage controlled current source Transconductanc e amplifier Siemens V V Voltage controlled voltage source Voltage amplifier Unitless Ohm

AMPLIFIER Each type of amplifier in its ideal form has an ideal input and output resistance that is the same as that of the corresponding dependent source Amplifier type Dependent source Input impedance Output impedance Current CCCS 0 ∞ Transresistance CCVS 0 0 Transconductance VCCS ∞ ∞ Voltage VCVS ∞ 0 In practice the ideal impedances are not possible to achieve. For any particular circuit, a small-signal analysis is often used to find the actual impedance. A smallsignal AC test current Ix is applied to the input or output node, all external sources are set to AC zero, and the corresponding alternating voltage Vx across the test current source determines the impedance seen at that node as R = Vx / Ix

OPERATIONAL AMPLIFIERS PARTICAL OPERATIONAL AMPLIFIERS CIRCUIT : 1 - INVERTING AMPLIFIRE :

OPERATIONAL AMPLIFIERS

2 -NONINVERTING AMPLIFIER :