Transistor Circuit Configurations: Common emitter, common collector, common base

When using transistors there are three basic circuit configurations that can be used. These are the common emitter, common collector or emitter follower and the common base ones.
In this video I explain the basics of these circuit configurations, giving the basic circuits and explaining the characteristics and advantages of each.
The first and possibly most common is the common emitter circuit. This is used in many amplifier circuits as it gives a good level of gain. It gains its name because the emitter electrode of the transistor is common to both the input and output circuits.
The common emitter circuit configuration gives a medium level voltage gain and a medium level of current gain, providing a high overall power gain level. The output is inverted compared to the input and the input resistance or impedance is medium as is the output resistance or impedance.
The common collector configuration has the collector common to both input and output. It has a unity voltage gain, a high current gain, and as a medium power gain. The output is in the same phase as the input and the input resistance is high whereas the output resistance is low making it an ideal configuration for use as a buffer amplifier.
Finally the common base which may also be called a grounded base because the base is typically grounded as it is common to both input and output. It has a high voltage gain, a /ow current gain and a low power gain. The input and output are in-phase and it offers a low input resistance or impedance as I've mentioned and a high output resistance. As the base is grounded it can isolate the input from the output making it ideal for RF circuits where stability is important.
More information about transistor circuit configurations:
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[@nonokodog622]

Always found the common-base to be the hardest to grasp.

[@ElectronicsNotes]

Likewise - it isn’t as intuitive, and although not very widely used it can be a lifesaver in certain situations because of its low input impedance and for RF circuits because it isolates the input & output because if the grounded base.

[@leonsoviac5380]

Short good explanation.

[@ElectronicsNotes]

Thank you.

[@SlyerFox666]

Much appreciated 👍

[@ElectronicsNotes]

Glad you appreciated the video - thanks for your comment.

[@Amperekaefer]

Danke 👍und LG.

[@ElectronicsNotes]

Glad you appreciated the video. Thanks for the comment.

[@mpip9701]

Since you noted a medium voltage gain for the common emitter, I would tend to also consider a medium voltage gain for the common base circuit for consistency (for their optimal use case of course), you don't think not ?

[@ElectronicsNotes]

I need to ponder on this. It’s a good point. I’ll go and double check this.

[@stalkerfromvoronezh4493]

Общая база еще и очень широкоаолосна. Ее используют во входных каскадах усилителей радио частоты.

[@ElectronicsNotes]

Indeed, I have used it in an RF amplifier and have seen it in many front end sections of radios using both BJTs and FETs