Push-Pull Pair - Class B, Class AB and Class A operation

In this video, Gregory explains the working principle behind push-pull pairs or complementary emitter follower stages. The differences between Class B, Class AB and Class A of operation are discussed, and a practical circuit is explained and develop for demonstration on the bench.

00:22 - Working principles
08:03 - Biasing for Class B operation
10:54 - Improvements by Class AB
14:26 - Current waveforms
15:55 - Condition for Class A operation
16:41 - Output impedance discontinuity in Class AB
20:38 - Bench circuit description
27:42 - Waveforms on the scope
33:09 - Ending

Push-pull stages are fundamental building blocks of electronics design and are present in all kinds of circuits, from high power, high fidelity and digital high speed.

Many operational amplifier use push-pull stages on the output to provide low impedance to drive real world loads. Many analog or digital signals need to be transmitted with matched impedance lines, and this kind of output stage provides the power gain necessary for signal transmission even between different signal domains.

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[johnnyshinnichi]

I have been watching youtube videos on electronics for years, but I have never seen anyone explain the operation of amplifiers as clearly as you. For the first time I actually understand how an audio amp works. Well done and thank you.

[donandmaudevandis]

Probably the clearest explanation I've ever seen. Excellent presentation

[prydin]

I’ve seen this explained about a million times, but this video highlighted some subtleties that I never considered before. Well done!

[RussTanner]

This is the best explanation of class a, ab, and b that I have ever seen. Excellent! Thank you,

[KGrasso]

Ive tried to understand how these amplifiers work for awhile now and usually shut a video off shortly after starting because I'm lost. Your video has been the best and I finally have a clear understanding of how class A, AB, and B work!

[cpunter]

Excellent teaching! Where many videos explain too little and others over complicate things, your explanations are perfectly clear. Thanks very much!

[creativetoday]

I am sure that you are a treasure for me in the science of electronics, because no one can explain like you. The only obstacle is that I do not understand English, but thank God this video is translated into Arabic. I hope that all your videos will be like this. Thank you very much, creator of electronics. Thank you very much.

[MrRadbadger]

You're a natural teacher Gregory. Keep up the great work!

[isuckatthisgame]

First time on your channel. I'm amazed by the amount of devices you've got here. Outstanding!

[egomezmx]

2 years latter, thanks for this very clear explanation, the best yet of a push-pull configuration

[GianfrancoTronu]

Beautiful video ! In addition to the technical content, I would add that your clear way of expressing yourself and your slow pronunciation is of vital importance to me, since I am Italian.
Well done !

[ReyciclismoMTB]

No doubt the best explanation on the net. Most are too superficial, you do a great class, white board and then actual build and test. Keep at it, making videos is tough, subject matter tricky. Awesome work. Thanks

[rubenhidalgocarrillo]

Excelent. The most clear explanation I've ever seen about amplifiers

[souflikar]

Very nice explanation and example. Well done!

[VeraConniff]

It's one of the best videos on Youtube. Thanks.

[stevesfascinations]

Thank you Gregory, I think your English is quite good. Thank you for explaining the topic so well.

[hubercats]

Excellent explanation of push-pull amplifiers. You would make an excellent electrical engineering professor. Thanks for sharing your expertise!

[davidatrakchi]

Fantastic explanation and demonstration!

[louisdesipio]

you can not disagree with your perfection! keep teaching !