Yes, case is closed, like a Perry Mason case. (LOL)

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Dear, dear Parasuraman...

You always had and you still have my full respect. No question about that.
At last I read from you words of wisdom not seen in the first place, as I expected, but nevertheless they are here no matter the delay. Your explanation about your experience and practicing being technically unacceptable simply confirms what I had suspected. Therefore is fully acceptable. It happened to me as well. You are not the only one being led in wrong technical conclusion(s) standing on a wrong base. There are many people and there will always be many others falling in such pitfalls, but this is quite natural. Knowledge is obtained through difficult ways and paths.
The point is if our "ego" is so strong that rejects unexpected "incoming signals", or flexible enough in order to realize that "it is a good chance to learn something new here"...
In any case I can assure you about a few things.
First, that I am not hurt by you in any way and therefore your apologies have no reason to exist.
I would rather reverse your phrase, putting myself in your shoes. The apologies in this respect are mine.
Next to that, be sure that you will receive again similar comments from me, under the same light of view, every time I will see statements that violate the established theory.
At this point, I must make clear once again that I am not talking about "my" arguments with the possessive meaning of the word, but with the meaning of the established theory on which my argument stands.
This simply means that I have always available the theoretical proof about my own technical statements when commenting, while I remain silent when it comes in things I don't know, but which trigger me to search about their truth for their further acceptance of them of myself.
In any case, my purpose was always to bring in surface what is scientifically correct, rejecting what it is not.
I can also assure you that I can read the feelings of a person's writings when it comes to interpersonal relations...
After reading very carefully every single word of your last comment, I would like to reassure you that I have never had hard feelings against you, neither against anyone else (especially of the article authors of this blog, being myself one of them).
Therefore,...case closed.

My best regards!

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Yes, very clear and vivid. Many thanks. You are further right that we need people who criticize than appreciate, as the former will always teach us something and help us think differently from our usual path. Your contribution, therefore, is welcome and special thanks for it. There was no sarcastic intention as assumed by you in that exclamation mark. It was an exclamation of appreciation. I fully agree with your technical arguments. But what I have practiced and experienced has taught me this, though technically unacceptable. Kindly therefore bear with me! My apologies if I have hurt you in any way. I never want to hurt anyone and will not even think of it directly or indirectly. (By the way, I never realized until now that an exclamation mark can lead one to misunderstand) I look forward to your expert comments and guidance in future also.

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You are right Paul.
Analog instruments, when measuring resistance and when changing ranges, put out different currents. Not different voltages. These ranges behave like constant current sources rather than voltage sources. Their voltage output simply depends upon the number of batteries included in the instrument, for the relevant measurements (I.e. 1,5V if there I’m only one alkaline battery included in it, or 3 V, if there are two of them connected in series). There are some cases where for the Rx10KΩ range exclusively, a 9Volt battery is also included. My first instrument was using a 22V battery for this range, not being available nowadays.
On the other hand, this fact about the number of batteries and their nominal voltages, explains clearly their function, based on Ohm’s Law, in combination with Kirchhoff’s current Laws...

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Many thanks!

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Many thanks, my friend!

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Hi Parasuraman

No matter the exclamation mark you put in your closing phrase, I can easily see hostility in your answer, which led me to answer you again, just in order to clarify at least how I am thinking, given our cultural differences which are unavoidably always present.
In any case, my purpose is not to insult others through commenting. On the contrary, I always seek the truth and when I find it I defend it later on.
I read your text again and again as regards the part of transistor testing. Your argument was that you replaced these transistors because of “uneven” indications. And then you explained the failure upon this base.
Unfortunately, there was never “even” indication and there will never be, as regards BJT transistor junctions B-E and B-C. Their Vforward will ALWAYS differ.
This is due to the fact that the emitter of the transistor is more heavily doped with silicon. This in turn makes the Vf voltage of the B-E junction a little bigger than the one of the B-C.
The difference is hardly seen with an analog meter, but it’s always there. Measured with a digital multimeter, it’s just a few millivolts above the B-C junction.
I magnified the relevant photos you published. This fact is present on both pairs of them. The second one is simply more obvious.
There are only a few exceptions to this rule (the assymetrical junction voltages I mean). I just remember the germanium type AC130, used in transistorized B/W TV circuits, in the synchronization separator stage. It was characterized as a symmetrical transistor directly on the schematic notifications, along with the instruction “the stage won’t work with any other replacement”.(SABA sets)...
Next, you say in your text, that this assymetry justifies leakage of the transistor. But this is not true.
Leakages are revealed when the polarity of the test voltage is reversed. Not when measuring Vf, which detects only shorts and opens.
You answered me that you follow Jestine Yong’s instructions...
I support the idea that a pupil should follow his teacher’s instructions, but teachers are not mistake-less. They are humans, not supermen.
In this case, about the range of testing small signal transistors:
How can one believe that a transistor of this family which normally has its base working in the μA range (an ordinarily high “beta” type), would happily accept 150mA in its base? Well, my teacher obviously didn’t!
I would agree in using this range only with power transistors, like the good old 2N3055, but never with a 2N3904...
Apart from all of these above, my idea about commenting an article, is, of course to recognize the effort the author put on it, this is obvious, but there is also another aspect always present.
A published article, teaches people. Especially newcomers in the field. These people need solid base in order to learn things about electronics.
Eventually the author is willy-nilly exposed to a large number of readers. They will react according to their accumulated knowledge. You need to accept that!
And the question is, how do you expect them to react when they see wrong ideas spreading all over the community these articles are targeted to?
And let me closing with a motto:” The person that always tells you that you are good and mistake-less, is not worth your trust, nor being considered as a friend of yours”.
Hopefully I made myself clear, which was my exclusive intention...

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