I have been absent here for a couple of weeks. Went on a road trip. I like to visit small museums around the country. The kind you find in tiny towns. I went to Minnesota to visit my daughter and grand kids. It is only about 950 miles but I took 3 days to get there. I suppose Australians call it walkabout. I did keep up with the stack, but not the chat.

I didn't participate, however I was delighted to see that the questions about use age of LED strips diminished.

But was disappointed that so many of the questions were about, " I was wondering", and. "What if I did this"

So, that is my rant for the evening. And looking forward to more challenging questions.

@NickAlexeev. . thanks for the heads up on the induction heating question a few days back.

@VoltageSpike. . . love your name. My business partner and I used to play Duke Nukem, and he used the name MEGAWATT

@NickAlexeev. The induction question about rebar : All local governments now require rebar to be epoxy coated. It extends the life of the reinforced concrete. And of course induction heating is used to cure the epoxy onto the rebar. You will notice the Green color coating when you drive by the the rebar on the roadway when new bridges are being constructed.

electronics.stackexchange.com/questions/449477/… .

please help me solve this problem.

with regards,

@ScientistSmithYT You have a really belligerent stance on scientists and their work. You seem to expect a step by step "build it book" from their experiments and papers.

That's not what it's about. In general, the experiment is about something else and the equipment (how ever complex it may be) is just a means to reach other goals.

How much good would it do if CERN published a complete set of blueprints of the LHC? You still couldn't build one.

I have seen papers where the exact materials used were listed and described - and people trying to replicate it 10 years later couldn't purchase certain components any more, and the original paper didn't describe how or why those components were chosen. Now what?

If your paper is a "Revell construction plan" for a 1T electromagnet, it will be unusable in just a few years because of changes in technology and parts availability.

please don't overlook my request

only thing i need is the assurance if my process of solving is correct?

Chill out dude, don't be a nuisance

few hints would suffice

Vo = V_thev1*[R_thev2/(R_thev2+Rthev2+R3)]

Vo = A*Vid*[R4/(R4+Ro)]

I'm probably wrong.

@TeilZeitGott ^

Vo=f(A,V1,R1,R2,R3,R4,Ro)

Vout must be the function of those params

I don't know how you'd solve it without Vid

Oh, and I am definitely wrong

how would you approach this sort of problem?

Vo = V_thev1*[R_thev2/(R_thev2+Rthev2+R3)] - A*Vid*[R4/(R4+Ro)]

Why can't you include Vid?

'they' want it like that

ohh, just make another node equation

Vid/R2 = (Vid-V1)/R1 + (Vid-Vo)/R3

Vid(1/R2 - 1/R3) = (Vid-V1)/R1 - Vo/R3

eh, screwed that up again...should do it on paper...

Something like this:

Vid(1/R2 - 1/R1 - 1/R3) = -V1/R1 - Vo/R3

Vid = [-V1/R1 - Vo/R3]/(1/R2 - 1/R1 - 1/R3)

Vid = [V1/R1 + Vo/R3]/(G1 - G2 + G3)

...

Vo = V_thev1*[R_thev2/(R_thev2+Rthev2+R3)] - A*[V1/R1 + Vo/R3]/(G1 - G2 + G3)*[R4/(R4+Ro)]

and that too is wrong =)

i will show u the correct answer.

Vo = V_thev1*[R_thev2/(R_thev1+Rthev2+R3)] - A*[V1/R1 + Vo/R3]/(G1 - G2 + G3)*[R4/(R4+Ro)]

im having a hard time getting that answer

which?

wait a moment!

just solve the rest, then check when you're done

ok! thanks for your effort

:-)

in the case of Ideal op-amp, node current at input terminal links output, and input voltages. but when the input terminal voltage difference is not zero, my hunch is Vid should be replaced with Vo/A.

@AdamUraynar thanks again

Maybe Vo = [V1/R1 - A*V1*R4]*[R3(G1 - G2+G3)(R4+Ro) - R4]/[R3(G1 - G2+G3)(R4+Ro)*R1(G1 - G2+G3)(R4+Ro)]

@Marla glad you like it.

@JRE Its not as it all seems. The part about how I want a "build it book" is entirely the wrong idea. There are certain things that are needed to make an electromagnet. These are called fundamentals. Whether they change in 100 years, its possible. What I am saying is this...

@JRE They are missing the smaller major fundamentals. That's what they don't tell you. It would be like taking apart an old car and not paying attention to how it was taken apart. With no instructions, or user manual. You have all of the parts, but your missing the fundamentals. The one portion that is needed to put the car back together.

@JRE They can say here's how you do it. But if you have made electromagnets for most of your life there are small things you'll notice that they don't have. And they are the smaller very important parts that are needed.

@ScientistSmithYT The point is that to an academic scientist, it doesn't matter how you put the car together. It only matters that you've demonstrated some basic principle, like "a gasoline engine can deliver X amount of power".

If you want to replicate their result, it's on you design and build a car that's efficient enough to extract that much power from gasoline.

@ThePhoton True.

@ThePhoton That's my point, this kind of stuff is very well known and well studied. But the practice of creating something like this is not very well known nor well studied.

@ScientistSmithYT They would be demonstrating some aspect that isn't well studied. But they wouldn't spend words in their journal article on the parts of the experiment that they consider previously well studied, or implementation details not related to the new result they're trying to produce.

@ThePhoton The electromagnet I want to make I will have something like a main parts list, and other sub parts. The parts I will use will no longer be sold in a few years. And that's why I will also update or I will give other parts and names that can also work to extend the expirary date to 1 or 2 years later.

@ThePhoton With my book that I continually add things to. I write it as if someone is new to the idea. I want it to be a universal book that everyone can read and understand.

@ThePhoton I never want my research or projects to not be recreated. And if something I do cant be recreated I say that it can't be recreated.