Briefly discuss about cascaded amplifier, Electrical Engineering

Assignment Help:

Q. Briefly discuss about ‘Cascaded Amplifier' using a diagram?

Amplifiers are cascaded when the output of the first is the input to the second. The combined gain is

1687_Briefly discuss about Cascaded Amplifier.png

where vi2 = vo1. The total gain is the product of the cascaded amplifier stages. The complication in calculating the gain of cascaded stages is the non-ideal coupling between stages due to loading. Two cascaded CE stages are shown below.

2199_Briefly discuss about Cascaded Amplifier1.png

Because the input resistance of the second stage forms a voltage divider with the output resistance of the first stage, the total gain is not the product of the individual (separated) stages.

The total voltage gain can be calculated in either of two ways. First way: the gain of the first stage is calculated including the loading of ri2. Then the second-stage gain is calculated from the output of the first stage. Because the loading (output divider) was accounted for in the first-stage gain, the second-stage gain input quantity is the Q2 base voltage, vB2 = vo1. Second way: the first-stage gain is found by disconnecting the input of the second stage, thereby eliminating output loading. Then the Thevenin-equivalent output of the first stage is connected to the input of the second stage and its gain is calculated, including the input divider formed by the first-stage output resistance and second-stage input resistance. In this case, the first-stage gain output quantity is the Thevenin-equivalent voltage, not the actual collector voltage of the stage-connected amplifier. The second way includes interstage loading as an input divider in the gain of the second stage while the first way includes it as an output divider in the gain of the first stage.

By cascading a CE stage followed by an emitter-follower (CC) stage, a good voltage amplifier results. The CE input resistance is high and CC output resistance is low. The CC contributes no increase in voltage gain but provides a near voltage-source (low resistance) output so that the gain is nearly independent of load resistance. The high input resistance of the CE stage makes the input voltage nearly independent of input-source resistance. Multiple CE stages can be cascaded and CC stages inserted between them to reduce attenuation due to inter-stage loading.


Related Discussions:- Briefly discuss about cascaded amplifier

Fsk scheme, Question: (a) An FSK Scheme is used in a wireless transmi...

Question: (a) An FSK Scheme is used in a wireless transmission with the data bits 1011010. With the help of a labeled diagram, describe in detail the final output of the MSK

What is induction machines, Q. What is Induction machines? We shall fir...

Q. What is Induction machines? We shall first consider polyphase induction motors and then single-phase induction motors. The polyphase induction motors used in industrial appl

Determine variation of large scale integration chips, Large scale integrati...

Large scale integration chips have between (A) Less than 10 components.         (B) 10 and 100 components. (C) 100 and 1000 components.       (D)  More than 1000 componen

Cro, what is cro ?

what is cro ?

What is the procedure of binary subtraction, Q. What is the procedure of Bi...

Q. What is the procedure of Binary Subtraction? The Rules of Binary subtraction 0 - 0 = 0 0 - 1 = 1 , and borrow 1 from the next more significant bit 1 -

Calculate the rms voltage generated in each phase, Q. Consider an elementar...

Q. Consider an elementary three-phase, four-pole alternator with a wye-connected armature winding, consisting of full-pitch concentrated coils.  Each phase coil has three turns,

Explain djnz instructions of intel 8051 microcontroller, Explain DJNZ instr...

Explain DJNZ instructions of intel 8051 microcontroller? a) DJNZ Rn, rel Decrement the content of the register Rn and jump if not zero. b) DJNZ direct, rel Decreme

Controls and system, transfer function of Lube Oil Cooler Temperature

transfer function of Lube Oil Cooler Temperature

Measurement and control systems, Electronic signals are used by almost all ...

Electronic signals are used by almost all measurement and control systems to transfer information. Much of this data is in the form of analogue voltages, which are prone to the ef

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