Effect of Negative Feedback on Bandwidth: The effect of negative feedback on bandwidth is given below as From Eq. (19.8) voltage gain with feedback is given as and from the above result it may be concluded that the voltage gain may be made to depend entirely on the feedback network. However, it is now important […]
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Effect of Negative Feedback on Output Impedance: Just as high input impedance is advantageous to an amplifier, so is low output impedance. With lower output impedance, the amplifier is better suited to drive a low impedance load. Such a desirable characteristic can be had by employing negative feedback. The Effect of Negative Feedback on Output
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Effect of Negative Feedback on Input Impedance: High input impedance is always desirable in an amplifier as it will not load the preceding stage or the input voltage source. Such a desirable characteristic can be had with the help of negative feedback. The Effect of Negative Feedback on Input Impedance of an amplifier is explained
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Characteristics of Negative Feedback Amplifiers: The Characteristics of Negative Feedback Amplifiers are given below Stabilization of Gain With Negative Feedback: The variations in temperature, supply voltages, ageing of components or variations in transistor parameters with replacement are some of the factors that affect the gain of an amplifier and cause it to change. However, the
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Advantages of Negative Feedback Amplifier: There are numerous advantages of negative feedback amplifier which outweigh its only drawback of reduction in gain. Among the advantages are : 1. Gain Stability: The voltage gain of an amplifier with negative feedback is given as Af = A/(1 + Aβ). If Aβ >> 1 then the expression becomes Af =
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Feedback Amplifier – Block Diagram, Definition, Operation and Types: Figure 19.7 represents the block diagram of an Feedback Amplifier. The output quantity (either voltage or current) is sampled by means of a suitable sampling network (or sampler) and is fed to the feedback network. The output of feedback network, which has a fraction of output
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Transresistance Amplifier – Definition and Equivalent Circuit: In transresistance amplifiers the input signal is current and the output signal is voltage. The ideal transresistance amplifier provides an output voltage in proportion to the signal current, and the proportionality constant is independent of the magnitudes of Rs and RL. From the equivalent circuit of a transresistance
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Transconductance Amplifier – Definition and Equivalent Circuit: In transconductance amplifiers the input signal is a voltage and its output signal is a current. The ideal transconductance amplifier provides an output current which is proportional to the signal voltage and the proportionality constant is independent of the magnitudes of Rs and RL. From the equivalent circuit
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Current Amplifier – Definition and Equivalent Circuit: The input signal in a current amplifier is essentially a current, and thus the signal source is most conveniently represented by its Norton equivalent (Fig. 19.3). The output quantity of interest is current. The current amplifiers is essentially a current-controlled current source. The equivalent circuit of a current
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Voltage Amplifier – Definition and Equivalent Circuit: Voltage amplifiers are intended to amplify an input voltage signal and provide an output voltage signal. The voltage amplifiers is essentially a voltage-controlled voltage source. The input impedance is required to be high and output impedance is required to be low. Since the signal source is essentially a
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