BJT- Common Base Amplifier Explained

In this video, the Common Base Amplifier is explained in detail. And the expressions of the voltage gain, the input impedance, and the output impedance of this common base (CB)amplifier are also derived during the discussion.

By watching this video, you will learn the following topics:

0:00 Introduction

0:40 What is Common Base Amplifier

3:37 Small Signal Equivalent Circuit of CB Amplifier

4:52 Voltage Gain of Common Base Amplifier

8:32 Output Impedance of the Common Base Amplifier

9:43 Input Impedance of the Common Base Amplifier

14:06 Common Base Amplifier with Voltage Divider Bias

Common Base Amplifier:

In Common Base Amplifier, the input is applied between the emitter and the base terminal, while the output is measured between the collector and base terminal.
So, the base terminal is common between the input and output side, and hence this amplifier configuration is known as the Common Base (CB)Amplifier.

The Common Base Amplifier provides a high voltage gain, low input impedance, and high output impedance.

During the discussion of the CB amplifier, the expressions of the voltage gain, the input, and the output impedance are derived in the video.

Application of CB Amplifier:

CB amplifiers are commonly used at the high frequencies for the impedance matching. (Because of its low input impedance)

The link for the other useful videos related to Small Signal Analysis of BJT:

1) BJT Small Signal Analysis: Common Emitter Fixed Bias and Voltage Divider Bias

2) BJT Small-Signal Model:

3) BJT Large Signal Model:

4) BJT- Emitter Follower (Common Collector Amplifier)

This video will be helpful to all the students of science and engineering in understanding the common base amplifier.

#CommonBaseAmplifier
#CBAmplifier
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[ALLABOUTELECTRONICS]

Timestamps for the different topics covered in the video:

0:40 What is Common Base Amplifier

3:37 Small Signal Equivalent Circuit of CB Amplifier

4:52 Voltage Gain of Common Base Amplifier

8:32 Output Impedance of the Common Base Amplifier

9:43 Input Impedance of the Common Base Amplifier

14:06 Common Base Amplifier with Voltage Divider Bias

[aliusef]

Dude you are a legend, Most of colleges & electronic book (except Floyd) were terrible at explaining CB amplifier. But you have nailed it💯

[parikshit]

Dude I was struggling with the small signal analysis....due to your buttery smooth it's completely clear to a lot just made me fall in love with the Analog you

[stormz]

Thank you very much. You are a great teacher.

[ammarasad]

you truly rock this subject ....loved your lecture and appreciate your effort...thanks

[Parirash]

Thank you for making this video. It helped to refresh the basics. Interesting thing was you didn't follow conventional textbook approach to explain CB. Approach was more from practical point of view.

Another possible application of CB amplifier is VCO used for FM transmitter.

[ishworirish]

Cleared some of the concepts, I was struggling with. Thank you

[devikadas]

I am amazed by the way your videos are made. They are very informative and understandable! Thank you for the videos😁 I would like to know how you draw these circuit diagrams as they are very clear and good. Is there any particular software?

[MAHMUDURRAHMAN-pkgm]

At 5:26 while finding out Vin, Can i write Vin =( Ie * Re)? if so then the Vin becomes equal and negative to Vout and the gain becomes -1.

[radekch.]

I think input can have another transistor in common emiter configuration so it can be used to increase power of another common emitter amp on output

[mercy.m]

what if there was no coupling capacitor between the emitter resistor and the AC input voltage?

[farhanupaul]

From the small signal we can find the voltage gain, but isn't BJT mostly used as a current gain device? How do we find the current gain? from regular DC analysis?

[mercy.m]

What happens if the load resistor is connected to the collector terminal and the source resistor is connected to the emitter terminal in terms of the voltage gain

[farhanupaul]

Why does tx lines need low input impedance amplifier? Is it to match with tx lines low impedance so no reflection wave occurs?

[Hmi]

Please sir explain this amplifier parameters calculation using h parameter model in presence of hoe parameter.

[tanumoypramanik]

Sir plz upload rc coupled amplifier and tuned amplifier

[surendra-gmfe]

Please refer in fig beside explanation!