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-cave-kludges/tree/main/Transistor101/Ep006_Biasing 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/by/4.0/