Circuit Stories

I  answered  this  SE EE question  on June 3, 2023. This is my latest (to date) CircuitLab story dedicated to the famous TTL logic gate family. How do we demystify TTL output stage? TTL circuits are some of the strangest creations of circuit designers (perhaps rivaled only by ECL circuits). If we type in the Google window "transistor-transistor logic", more than 18 million pages will pop up telling us "this is so..." but we will hardly find any pages that say "why this is exactly so..." We have no choice but to try to answer our own questions. There are two oddities in these creations - first in their input part and then in their output part. Here, the object of our attention is their output part. Reinventing TTL output stage I am not a circuit designer, just a "circuit thinker"... and I can only guess what the designers had in mind in the 60's. What I can do is try to reproduce their train of thought in the form of an imaginary pseudo-invent...

At the beginning of this year, I started working with the  CircuitLab  simulator. Here is a list of links to my best CircuitLab stories so far: How does a transistor inverter work?  is my first CircuitLab story laid out in four consecutive steps (frames). There are no graphs of the simulations (the topic does not require it). How does this rectifier work, since the op-amp input is 0 V?  is my first full CircuitLab story, laid out in five "frames".  In addition to schematics, I have richly illustrated it with graphs  from the simulations. Why do we need R1 in a non-inverting op-amp?  is a lush story, in which I first applied schematic framing (to unify scale). Need clarification regarding op-amp's ground/ reference and common mode dependence on supply  is dedicated to the famous differential ("long-tailed") pair. To show the basic idea behind it, I have built it step by step. How does an op-amp know where ground is?  is another story dedicated...

 The prerequisites For a very long time, years, I have refrained from working with programs for simulating electrical and electronic circuits. I thought they would get in the way of my creative thinking. I have preferred to imagine for myself, with the power of my imagination, intuition and practical sense gained through real experiments and practice, the operation of circuits. I have often joked that "my brain is my simulator" :-) My concerns have been that simulators are heavy and clunky, often wrong, and require a lot of expertise to get them to correctly represent the operation of the circuits. So, I thought, I can never be sure of what they show. I have generally thought that simulations are for formal, logical-minded people who are more mathematicians than technicians. I do not know if it was just me or it is generally like that, but I have always been surrounded by such people - smart, knowledgeable... but not understanding. For them, circuits are  something existing, ...

Това са линкове към най-силните ми  CircuitLab  истории от началото на годината: How does a transistor inverter work?  е първата ми CircuitLab история, изложена в четири последователни стъпки (кадъра). Няма снимки от симулациите (то и темата не изисква). How does this rectifier work, since the op-amp input is 0 V?  е първата ми пълноценна CircuitLab история, оформена в пет "кадъра". Освен със схеми,  съм я илюстрирал богато с времедиаграми от симулациите. Why do we need R1 in a non-inverting op-amp?   е пищна история, в която за първи път съм приложил рамкиране на схемите (за уеднаквяване на мащаба). Need clarification regarding op-amp's ground/ reference and common mode dependence on supply How does an op-amp know where ground is? Puzzled with parallel forward biased diodes with common anode and different cathode voltages  е  дълга история, в която разкривам философията на изходните стъпала. Non-inverting op-amp  е много дълга и богато илюст...

Предпоставките Много дълго време, години наред, аз съм се въздържал да работя с програми за симулиране на електрически и електронни схеми. Смятал съм, че те ще попречат на творческото ми мислене. Предпочитал съм сам, със силата на своето въображение, интуиция и практически усет, натрупан чрез реални експерименти и практика, да си представям действието на схемите. Често съм се шегувал, че "моят мозък е моят симулатор" :-) Опасенията са ми били, че симулаторите са тежки и тромави, често грешат, и се иска много опит, за да ги накараме правилно да представят действието на схемите. Така, мислех си аз, никога не може да сме сигурни в това, което те показват. Като цяло съм смятал, че симулациите са предназначени за хора с формално, логическо мислене, които са по-скоро математици, отколкото техници. Не знам дали само при мен е било така или по принцип е така, но все съм бил заобиколен от такива хора - умни, знаещи... но неразбиращи. За тях схемите са даденост, нещо съществуващо, сяка...