Transistors 101 ep6: Biasing and Bootstrapping

We examine three emitter follower circuits with different designs for their biasing networks.

The first one is designed lazily, and results in clipping of the signal.
(Simulation can be seen at https://tinyurl.com/2khpdd8o).

The second one has the biasing improved, and no longer clips at the designed signal level. Simulation at https://tinyurl.com/2qy4yz42.

The third one has its input impedance markedly improved using a bootstrap capacitor. This follower is actually built and tested in the video, but has a simulation available at https://tinyurl.com/2h2w8n5y.

As usual, supplementary files are available on the project GitHub: https://github.com/kennykb/kevins-cav...

Timeline:

00:00 Intro
00:02 Biasing an emitter follower
06:58 Simulating the follower - oops!
08:36 What went wrong with the biasing?
10:31 Correcting the biasing
12:59 Bootstrapping for a better impedance match
16:38 Building and testing a bootstrapped follower
18:04 Outro

Music:

“Light Sting” Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 4.0 License
http://creativecommons.org/licenses/b...