Circuit Stories

My answer  to SE EE question  Common Base Amplifier Confusion This story is another case of rude administration in StackExchange EE. I tried to reveal in detail the operation of the legendary common-base stage by illustrating its operation with the help of voltage bars and current loops. But this did not become easy and required multiple edits to reach perfection. For some reason incomprehensible to me, however, the moderator did not like it and at one point he locked my answer.  The problem is that I improved Fig. 2 as I drew the paths of charging currents and I want to replace the figure. Also, I found Cyrillic letters in the captions under some figures and I want to correct them. I asked the moderator to unlock my answer (see the last comments below)... but so far I have not received an answer... Answer Common emitter and common base are formal terms; common collector is even meaningless. For the last time, I came to this conclusion during yesterday's laboratory exercise dedi

My answer  to SE EE question  JFET as an amplifier In the previous post I told how, аt the beginning of the new year, two interesting questions related to the well-known "biasing" technique in amplifiers arose in StackExchange EE... and how I enthusiastically answered them. Here is the second story... Answer Philosophy. In my answer I will try to expose the philosophy of this kind of biasing called "sorce (emitter, cathode) degeneration". Saying "philosophy", I mean not only to describe what is made but to explain why it is made this way... Problem. We have to ensure some initial input voltage across the gate-source junction so that the transistor starts working even before the input voltage is applied. This "bias voltage" should be stable so that the drain current is stable... and the DC output (drain) voltage is stable as well. Self-biasing. The clever trick of such self-biasing is that the transistor itself creates the necessary bias voltag

My answer to SE EE question Inverting Amplifier Not Applying Gain to Bias Voltage At the beginning of the new year, two interesting questions related to the well-known "biasing" technique in amplifiers arose in StackExchange EE. I was in an uplifted creative mood and enthusiastically started answering them. Here is the first sto... Answer Intuitive explanation Understanding. Apart from the detailed explanation of the specific circuit implementation accompanied by calculations, the real understanding requires something more - to see the basic idea behind it, how it is implemented in the specific case, where currents flow, what voltages across elements are and how they relate to each other. In doing so, we will get to the depths of the problem and not just glide across the surface… and we will be able to see the same basic idea in seemingly different applications. I will illustrate this for the specific circuit. Basic idea. The main OP's problem here is to understand the