Discussion between tlfong01 and Circuit fantasist

2:13 AM

0

A: Using a PNP over an NPN to activate a solenoid

Although it has been said several times, I will try to say it even more simply and clearly. The simple truth is that, in most cases, the input sources and next loads are connected with one (negative) of their two terminals to the negative terminal of the power supply assigned as a zero reference ...

Circuit fantasist

@‭ilkkachu, Thanks for the response. I mean the usual case for cascaded stages where the load is connected in parallel to the transistor. Really, here the load is connected in series to the transistor but that does not change things about the transistor (it is in the same place).

tlfong01

@Circuit fantasist, your mentioning of "cascaded stages" and "load is connected in parallel to the transistor" seems to make things more confusing. It would be nice if you can describe you circuit in more detail, or better still draw a schematic, which will be much appreciated.

I am trying to answer here your question "Where do you get this unbridled imagination from? And that subtle sense of humor? Maybe you are inspired by the Einstein's thought about imagination:)? The reason of not answering not as a comment in the answer where I wrote my story of "imagination" (actually a "prediction") seems to have disappeared into the future. / to continue, ...

Circuit fantasist

@tlfong01, My answer was more general - about a multistage amplifier, where the output collector-emitter part of the current transistor drives the input base-emitter junction of the next transistor acting as a grounded load. Actually, I have explained why NPN but not PNP transistors are widely used to build transistor amplifiers...

tlfong01

@Circuit fantasist, I see. So you have diverted a bit into analog amplifiers using push pull topology. Actually digital circuits can also do push-pull. I usually classify BJT digital buffer/driver outputs into three types: (1) Open Collector, sinking/pulling current from load, (2) Common Collector, sourcing/pushing current to load, (3) Push-Pull, can do sink/pull or source/push. The OP might like to see in my relay answer referred above, of examples of different output types in handling a relay. / to continue, ...

/ Continued, ... (1) Class-B Amplifiers - Electronics Tutorials electronics-tutorials.ws/amplifier/amp_6.html (2) Open collector Output (Sink current from a load) - Wikipedia en.wikipedia.org/wiki/Open_collector (3) Common collector Output (Source current to a load) - Wikipedia en.wikipedia.org/wiki/Common_collector (4) Push-Pull Output (Can sink or source from/to a load) - Ecircuit Center ecircuitcenter.com/Circuits/pushpull/pushpull.htm. Cheers.

Circuit fantasist

@tlfong01, You are an interesting person with this "philosophical" reasoning... I see some resemblance between us:) I just cannot agree with the term "common collector". Maybe "sourcing", "sinking" and "sourcing & sinking is a more appropriate determinant before "open collector"?

tlfong01

2:13 AM

(1)But open collector, common emitter, sink, source etc, are "official" terms used by the pros. You might like to watch this video RSD Academy - Open Collectors and Pull up Resistors youtube.com/watch?v=BH3u8E2UfSo, to see other pros are using these terms in an application of using opAmp(Comparator) to activate a relay, explaining the use of open collector, push/pull output, and pull up resistors etc.

About my "philosophical" reasoning", I have a BA degree in Philosophy and History, so I do have particular interest in using human language to explain hard to explain things (OK, like Einstein) and looking things in the past (PNP/NPN BJT) and predict things in the future (All MOSFETs in 2035). Predicting things in the near future is very important for IT pros in strategy planning and innovative/start up businesses. Ah, I also have an MA in Education, so I am interested to teach (or learn together) in a newbie friendly way, say, understanding by using metaphors. Perhaps more later.

Circuit fantasist

@tlfong01, Very interesting... I am glad there are people like you (and me:) here... and they have the courage to write that way. I am by vocation an inventor, a teacher and above all a "circuit thinker". I try to find basic ideas behind circuits... and it takes me years. Then I explain circuits by building (reinventing) them step by step and showing their evolution. I do it by using human-friendly explanations, analogies... and by visualizing the invisible electrical quantities. My circuit diagrams are conceptual but then I show various applications. But I cannot find followers... Why?

tlfong01

2:24 AM

I was curious to know why he doesn't have any followers?. So I googled to find out, starting from the web page referred in his profile. I began to feel uncomfortable when I entered the web page. It took me less than 3 minutes to find out one big reason why he has no followers. Then I thought: (1) He knows the answer already, but does not want to tell. If that is the case, then he is not honest, (2) He does not know the answer. It that is the case, then he is stupid, ...

tlfong01

4:03 AM

(3) I am numbering my questions so that it is easier to refer to the subject we are discussing. Now it is a question that I am asking myself - Can my answers attract more followers and therefore hopefully more down votes? You might have noticed that my popular answer of JD-Vcc relay has 10 upvotes but actually I still want to improve it. It is sort of self appraisal, SWOT analysis, postmortem techniques.

I know one of the good points of my relay answer are (a) It is on a subject JD-Vcc that causes confusion to many newbies. So I gave a comprehensive answer with a step by step learning case, with structured index, and (b) most importantly, with a lot of photos, and schematics.

Now let me ask another question (4) that is more or less a tip to my questions (1) and (2). When answering questions on circuit design using BJT, MOSFET, OpAmp, beside schematics using CircuitLab, I also wanted to use LT-Spice. But I don't know LT-Spice, so I am thinking of learning LS-Spice. Now my question to you it this, are you or have you been using Circuit, LT-Spice, or YouTube, TikTok, which I think should attract more followers?

Circuit fantasist

9:30 AM

@tlfong01, Again, I find that you are a very interesting person... not so typical of EE. I want to review your "popular answer of JD-Vcc relay" first to get an idea of how you think... and then I wll response to your message. Regards.

Circuit fantasist

2:52 PM

@tlfong01, First, about you… Today I read your answer about "JD-Vcc relay" and I got a very good idea of your way of thinking. I saw that, in addition to your "philosophical" thinking, you also have very good specific thinking... and a very good style of presenting. So, I think there is a chance you can understand me. Although for the "Arduino boys" your answer is great and very useful, for me it is quite specific...

… Here you can see some basic circuit ideas that are inherently electrical and were realized long before the "Arduino era" - even in the 19th century (well, not with transistors but with electromagnetic relays)...

... Arduino is just one of many possible implementations of these basic ideas and all these details interfere with the understanding of the simple and clear (electrical) idea. It turns out that today people get acquainted with the basic ideas of elementary electrical and electronic circuits through Arduino...

Now, about me… My purpose is first to reveal and explain the basic ideas behind circuits (concepts). I do it by using conceptual circuit diagrams with "ideal" and generic elements without specific values. Only then I show some specific implementations as examples.The power of this approach is that once understood the concept you can understand many other specific implementations.

Circuit fantasist

6:43 PM

In contrast, if you explain only the specific implementation and not the principle behind it, then you will have to explain each next implementation. In the first case, you will know (understand) only one principle, while in the second you have to remember many different implementations.

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Discussion between tlfong01 and Circu…