Amplifiers with feedback, Electrical Engineering

Assignment Help:

Q. Amplifiers with Feedback?

Almost all practical amplifier circuits include some form of negative feedback. The advantages gained with feedback may include the following:

• Less sensitivity to transistor parameter variations.

• Improved linearity of the output signal by reducing the effect of nonlinear distortion.

• Better low- and high-frequency response.

• Reduction of input or output loading effects.

The gain is willingly sacrificed in exchange for the benefits of negative feedback. Compensating networks are often employed to ensure stability.Avoltage amplifierwith negative feedback is shown by the generalized block diagram in Figure. The negative feedback creates a self - correcting amplification system that compensates for the shortcomings of the amplifying unit.

The gain with feedback can be seen to be

512_Amplifiers with Feedback.png


The product AB is known as the loop gain because vf = B(Avd ) = (AB)vd . In order to obtain negative feedback, the loop gain must be positive. With AB > 0 in Equation it follows that |Af | < |A|. Thus, a negative feedback amplifier has always less gain than the amplifying unit itself. With AB >> 1, Af remains essentially constant, thereby reducing the effect of transistor parameter variations in the amplifying unit. If the feedback unit has |B| < 1, one can still obtain useful amplification since |Af | = 1/|B| > 1.

These are also known as RC amplifiers since their circuits need only resistors and capacitors. There are of course other transistor amplifiers that do not have the small-signal limitation and are also not limited to the use of resistors and capacitors in their circuits. For larger input signals the linear dependence of the current on the signal level may not be maintained.


Related Discussions:- Amplifiers with feedback

Find the mmf needed to establish a magnetic flux, Q. Consider the toroid sh...

Q. Consider the toroid shown in figure made up of three ferromagnetic materials. Material a is nickel-iron alloy having a mean arc length la of 0.6 m; material b is medium silicon

Explain medium length lines, Explain Medium length lines? Medium length...

Explain Medium length lines? Medium length lines cover lines in the range of 50 to 150 miles (80 to 240 km). Due to the increased length of the line, the shunt capacitance of t

Ac resistance and dc resistance, Background Information Electrical mach...

Background Information Electrical machines usually consist of copper windings on steel cores, and their AC resistance is greater than their DC resistance. The power loss has

Use thevenin''s theorem find the current flow by resistor, Use Thevenin's T...

Use Thevenin's Theorem, find the current flow by resistor R=10Ω.

Senior Design Robotic Arm Project, This is basically a simple senior design...

This is basically a simple senior design project where the professors are giving us a limited budget and providing us with an Arduino Board. (We can use rasberry pi, beagle bone, e

Basic architecture of digital switching systems, Q. Explain the basic archi...

Q. Explain the basic architecture of digital switching systems. Explain in detail companding. Ans: A simple N X N time division space switch is displayed in Figure. Switch

Determine about the wireless technology, Determine about the Wireless techn...

Determine about the Wireless technology Wireless technology (WiFi) enables connection of a computer to Internet without the need for connecting cables. A router (comprising a m

Power Systems, are you able to help with power system

are you able to help with power system

Explain the transfer characteristics, Q. Explain the transfer characteristi...

Q. Explain the transfer characteristics in a few words ? The transfer characteristics are a plot of an output (or a drain) current versus an input controlling quantity. There i

A 450 ns eprom won''t work directly with a 5mhz 8088, A 450 ns EPROM won't ...

A 450 ns EPROM won't work directly with a 5MHz 8088.Why? Explain. While the 8088 is operated along with a 5 MHz clock, it permits 460 ns for the memory to access data. Due to t

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd