Noob Question About Current From Voltage Regulators

[davenn]

I know all of you know a lot more about electronics than I do, but no one really answers any questions.

in all your threads, people have been giving the best answers possible with the available info given by you

That should be a major hint to you that if you want even better answers, then you need to give better background info


Cheers
Dave

 

[Rory Starkweather]

You are not being obnoxious
and because you cant/wont post circuits/images we have no way to confirm what you are doing or what you may be doing wrong
Because of that all the questions have to start with the basics to try and figure out what is going on.

Others will post circuits and pics of the things they are building and or working on, that makes it VERY easy for others on here to diagnose possible problems and even to point out major mistakes in their wiring

You have previously admitted to poor eyesight, so it is reasonable for us to expect that you have made obvious wiring errors.

We all love to help people with their electronics .... none of us get paid for it ... we do it for the love of the hobby. And with that we need the person asking for help to help themselves and us as much as possible by supplying as much information as possible. We are not with you, we cannot pick up or look directly at the circuit you are working on, therefore you need to explain everything as clearly as possible

What are you using to access the internet ?
a PC compatible computer ? what operating system ?

Dave

AMD 8 Core. Win764. New install yesterday.New manual scanner, yesterday.

 

[KrisBlueNZ]

When I say 'attachment' it can only mean something that is real, not something that can be put on paper.

When you post in an international forum on the Internet, you're "not in Kansas any more", and to use another famous quote, "When in Rome, do as the Romans do". If you think your reason is a valid argument, well, be prepared to be misunderstood again in the future.

I've been doing this for 20 years now. You may have been doing it longer, but I do understand Ohm's Law. And even Ebers-Moll.
You don't seem to understand. I am neither 12 years old, nor stupid. I am just stuck with what the Marine Corps taught me.

No, you don't understand. We don't know what you do and don't know; sometimes, people know a lot about one subject but lack knowledge and experience in related areas; you are not the only person who will read this thread so comments aren't necessarily only directed at you.

 

[davenn]

AMD 8 Core. Win764. New install yesterday.New manual scanner, yesterday.

so you have absolutely no reason/excuse not to be able to draw circuits of your projects !

 

[Rory Starkweather]

I have an 8 core AMD running Win 7 64. but it's optimized for Lazarus, Modula-2, ADA and a few other non-mainstream apps. It's a trade off. I can go with one hobby, or the other.

But the concept that people can no longer visualize even a circuit that only has two components, frightens me.

Each component in the circuit above, has two leads. Plus and Minus. But you can't figure it out?

BTW. after burning up all the components, the 9 volt regulator was binned. No time or money for it.

Looking for something else now, that will do the same thing . . . except getting binned.

After nearly a month of research and experimentation, I am no closer to my goal. Maybe this isn't the correct forum?

 

[KrisBlueNZ]

After nearly a month of research and experimentation, I am no closer to my goal. Maybe this isn't the correct forum?

No doubt, that's the problem.

Your insults in post #18 and post #25 are unacceptable. I think you need to take a little holiday. A couple of weeks to start with. Perhaps you will use this time to find a proper forum that will answer your questions to your satisfaction.

 

[hevans1944]

... E was the original letter used for voltage. It stands for EMF, "electromotive force". I learnt Ohm's Law as "I = E / R" too. But at some time around the 1970s or 1980s I think, the convention was changed so voltage is represented by V. That's the only difference.

Yeah, I guess I showed my age on that one. I don't remember when usage changed from E to V for representing potential difference, but apparently it has. So I will try to remember this "new" convention in subsequent posts.

It is always a good idea when writing equations to explicitly define each symbol and the unit involved. This will avoid any confusion even if, say, we were to use the European (German, actually) convention of U to represent voltage. The problem really becomes apparent when reading highly technical papers where the authors use "obscure" Greek letters to represent variables. For some reason my brain has difficulty "verbalizing" some of these characters, such as ξ (small Greek Xi) and I still get confused with the Greek letters phi and theta (Φ,Θ respectively).

So, anyway, to avoid further confusion in this forum I will try to remember to use V for voltage instead of E or U. Thanks for pointing that out, Kris.

 

[Arouse1973]

Greek letters, me to.... don't even go there, and then they use lowercase just to confuse you
Adam

 

[KrisBlueNZ]

It is always a good idea when writing equations to explicitly define each symbol and the unit involved. This will avoid any confusion even if, say, we were to use the European (German, actually) convention of U to represent voltage.

I thought that "U" was used to indicate a voltage difference, rather than just a voltage. So for example the voltage across a series resistor would be denoted U_R1 to make it clear that it's not supposed to mean the voltage at one or other end, relative to 0V. I thought that was kind of a good idea. Maybe I just dreamed it all up?

 

[Gryd3]

I thought that "U" was used to indicate a voltage difference, rather than just a voltage. So for example the voltage across a series resistor would be denoted U_R1 to make it clear that it's not supposed to mean the voltage at one or other end, relative to 0V. I thought that was kind of a good idea. Maybe I just dreamed it all up?

How do you know which side if the reference? U_R1 could be a positive or negative value?
I like the idea, but it would confuse the heck out of me unless someone pointed that out to me.

 

[KrisBlueNZ]

In most, but certainly not all, cases, a resistor in a given circuit position only ever has one polarity of voltage across it, and that polarity is clear from the schematic. I never thought it was confusing. But as I said, this "U means voltage difference" might be all in my imagination!

 

[Ratch]

If I have a 2 Amp regulated supply, will the attached circuit have to drop the whole 2 amps, like voltage, or will it just take what it needs?

Hmm, maybe we should start again. The 2 amp specification of your voltage source simply means that it is capable of supplying up to 2 amps of current at whatever voltage it is set at. If your circuit draws more than 2 amps, the voltage source will probably blow its fuse. Any questions about that?

Ratch

 

[davenn]

Hmm, maybe we should start again.

probably a bit pointless since he has been banned for a bad attitude

 

[davenn]

in fact its probably pointless keeping the thread open since the OP isn't here

thread closed