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

Explain source encoding or data compression, Q. Explain Source encoding or ...

Q. Explain Source encoding or data compression? The sequence of binary digits from the source encoder, known as the information sequence, is passed on to the channel encoder. T

Semiconductors, Semiconductors Conductivity in among those of metal...

Semiconductors Conductivity in among those of metals and insulators. Conductivity can be changed over orders of magnitude through changes in temperature, optical excitat

Multiplexer, design a 32:1 multiplexer using two 16:1 multiplexer

design a 32:1 multiplexer using two 16:1 multiplexer

Compute the turns ratio and the winding current ratings, Q. A transformer i...

Q. A transformer is rated 10 kVA, 220:110 V (rms). Consider it an ideal transformer. (a) Compute the turns ratio and the winding current ratings. (b) If a 2-load resistance

RESISTACE, What is the value of a resistor marked as 47KK?

What is the value of a resistor marked as 47KK?

Find differential equation & state-space representation, 1. For the followi...

1. For the following network: a. Find the differential equation assuming that v ( t ) is the input and the charge on the capacitor q ( t ) is the output. Hints: i R1= ( i R2

Find the current and voltage drop at resistor, For the circuit in figure, f...

For the circuit in figure, find the current and voltage drop at every resistor

Chopper configuration - power supplies , Chopper Configuration Choppe...

Chopper Configuration Chopper are classified  in five  different classes according  to their operating capability in particular quadrant. The  current  directions and voltage

Transformer, Why we provide the short circuit and open circuit test in tran...

Why we provide the short circuit and open circuit test in transformer

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