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

Strategy and customer relationship management, Strategy and Customer Relati...

Strategy and Customer Relationship Management CRM sometimes considers as only information technology because of availability of quite a good number of software packages in the

Shunt dc motor, Shunt DC motor In this arrangement, the armature and f...

Shunt DC motor In this arrangement, the armature and field coils are connected in parallel (the motor is called 'shunt connected').     Analysis With refere

Features hindering developing countries from growing faster, Q. Describe so...

Q. Describe some of the features hindering developing countries from growing faster. Answer: One of the features that are able to be hold developing countries from growing fas

Compute the source current, Q. A 230-V, single-phase, 60-Hz source supplies...

Q. A 230-V, single-phase, 60-Hz source supplies two loads in parallel. One draws 10 kVA at a lagging power factor of 0.80 and the other draws 6 kWat a lagging power factor of 0.90.

What is threaded system, What is Threaded system. Threaded system: At...

What is Threaded system. Threaded system: At times we require implementing an operating system which can process multiple threads. Many threads are handled through the kernel

Explain the signals hold and sid, Explain the signals HOLD, READY and SID ...

Explain the signals HOLD, READY and SID HOLD indicates that a peripheral such as DMA controller is requesting the use of address bus, data bus and control bus. READY is used to

Find the diode current and voltage in given circuit, We shall demonstrate l...

We shall demonstrate load-line analysis to find the diode current and voltage, and then compute the total power output of the battery source in the circuit of Figure (a), given the

Led driver with dim function, I´m looking for some help to identify some el...

I´m looking for some help to identify some electronic parts, i have this led driver with preset dim levels that i can reach with switching the power on and off. The driver worked r

Logic Gates, A former employs a servant to look after his form house. He in...

A former employs a servant to look after his form house. He instructs the servant to keep a watch on his goat. So that he does not harm the kitchen garden, when the entrance-door

What will the slipring voltage be in this case, A four-pole, three-phase, w...

A four-pole, three-phase, wound-rotor induction machine is to be used as a variable-frequency supply. The frequency of the supply connected to the stator is 60 Hz. (a) Let the r

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