Electronics Fundamentals ARGUMENT/DEBATE

[DangerSeeker]

Ok, I have an argument with my instructor in this class. It's not so much the points missed on the test as it is the aspect in which he insists is correct. Though I would appreciate the point to get me back to 100%

Ohm's Law: Current is directly proportionate to Voltage and inversely proportionate to Resistance.

This verbage has been translated into a formula:
E
___
I*R

(E over I times R) or E / (I * R)

The question was, "According to Ohm's Law, what is the relationship between Voltage and Resistance".

Before I go into my argument, anyone here know for sure, and understand, the answer?

The answer he insists is they are NOT RELATED. Okay, now, I can understand the fact that Ohm's Law does not directly state a relation between the two, but this is not the same as having no relation. He also says that changing the Voltage will not change the resistance [yes, true], and vise/versa [only true with Applied Voltage], and that this is why there is no relation.

My argument is mathematical, and I would love to hear any sides of this. In an equation, if a variable is included, it is then related to all other variables in that equation. And as well, you can not just remove the voltage from that equation, as you will no longer have Ohm's Law. Therefore, by logical conclusion based on mathematical rules (the purpose of Ohm's Law being to put electronics into solvable equation), the Voltage is related to both the Current and the Resistance, as they all intermingle. If you were to plug in their values, the equation will always read:

E / (I * R) = 1

A quick example of relation in algebra:

X = 2 * Y
Z has no relation to X
Z = Y / 2
Z still has no relation to X, but if both are true (AND being the boolean, not OR), then X and Z has developed a relation:

X is four times Z [ x = 4Z ]
or v/v:
Z is one fourth of X [ Z = X / 4 ]

I believe to put in in an equation similar to Ohm's Law:

(Z + (X/4))/Y = 1 or in another form: Z + (X/4) = Y

Any math majors out there wanna throw in their two cents? Electronics folks? I'm a bit rusty in my math...so I hope I used the correct terminology.

[crystaldragon]

Just reading through your post. It looks like your instructor is basing his opinion on the concept that they (voltage and resistance) are not directly related, but that they interact. (a very fine distinction) In which case he can also argue that your mathematics demonstrate that point for him!

[DangerSeeker]

Actually, he said the opposite of what you just said...he's saying that they don't interact with each other, hence they are not related. [when I brought up that voltage is in fact altered by resistance (voltage drops and voltage outs), he states "...only in components," and they don't count because "we're only talking about total"]

It's that word: "Relationship". Is the definition of items having a relationship: "when ones changes, the other must also"? Maybe that's the vagueness that is plaguing me. If that is the only definition of Relationship that applies to electronics, then my argument ends here. Maybe it's the fact that I'm not sure why I'm supposed to assume that law is only for total numbers, yet we apply it to component values as well. Maybe I'm brain dead...no, I don't believe it.

And as for being directly related, all three items in that equation are just as directly or indirectly related. Related being the word, not proportional. Also, could you elaborate on the part of my math that proves they interact but are not related?

[capybara]

dude: as a BSEE and journeyman electrician,
i say your are right and your so called innstructor
is lame, annd merely splitting hairs. this sux.
you deserve the point. there is a diffferrence between trying tto teach, and trying
to prove your superior to your students.
this pi55e5 me off even thinking about it.

[cracked]

i can see both sides of the argument as true. if i was in your situation i prolly would have argued your point. if i was in his situation, i would have said what he said(if i was an @$$hole teacher, but being me, i would have at least given you half credit for having a good point about your argument). :-)

drew

[cadetstimp]

The question was, "According to Ohm's Law, what is the relationship between Voltage and Resistance".

Hmmm.... poorly worded and incomplete question ... should have been worded "According to Ohm's Law, what is the relationship between Voltage and Resistance in a single isolated circuit with a constant resistance" ...in order to get the answer he/she was looking for.

The Teacher may argue because it was stated "According to Ohm's Law", he/she was looking for a mathematical answer. Problem is "According to Ohm's Law" requires a situation to generate an accurate result regarding a relationship between resistance and voltage. A good answer to the teachers question would have been "According to Ohm's Law, the relationship between Voltage and Resistance is determined by the nature of the circuit(s) and the components involved".

What if the circuit included a potenialometer (sp) or involved multiple circuits with integral components? Then resistance and voltage could be related, right?

He/She probably took the question from prepared materials that came with the text instead of designing questions to test comprehension of the Law by applying the knowledge in real life situations. The question, as it was stated and expected to be answered, doesn't really teach much practical knowledge - almost mathematical trivia in comparison to the implications of applying and understanding Ohms Law.

Just an easy question for a teacher to come up with when generating a test (or when borrowing it from prepared materials that comes with the text). <edit> ....so easy and trival the teacher screwed up when phrasing the question in the first place </edit>

I feel your pain....this situation you're going through is why I’ve learned to like science teachers that prefer a lab environment or a practical attitude.

Also, teachers that enjoy their job as an interactive experience rather than mainly seeing a bunch of mindless legwork usually enjoy challenges from students interested in the "right" answer.

[RustyGT]

It would be, an Academic, to be so pendantic.
When the words, mean more than principle.
The study turns from "Engineering" to "Law"

So the Quiz is:
What are we doing?
Repairing the machine?
Or suing for damages, after it broke down?

Sheesh...

[HomeYield]

1) V = I*R
2) R = V/I

So your teacher is saying that if you change R in equation 1 that V won't change. If you change V in equation 2 would R not change. I'm not real verbose in mathematics nor did I do real well in my electrical engineering courses but it looks like there is a relationship between V and R with respect to I.

[RustyGT]

Gotta duck back in here.
V=IR. Ohms Law.
Fundamental [as mentioned]

Just as:
Pressure= Mass x Area
Why we use the water model.
For Electricity.

Did I miss something?
Or was it using the square root of a negative number.
That saw me fail Calculus in Senior?

Any of the three measurements can be variable.
Or vice versa.
Any of the three variables may be subject to measurement.

But at least two should be measured.
Before the third is calculated.

Crikey, It's not that hard!

But then I, like you, maybe wrong.
I vote for, jam his tongue in the toaster.

Then he can explain Watts Law.
P=VI or P=I [squared] x R.

[/rant] R.

[capybara]

Rusty: is that poetry you write in?
its worded so carefully
and paced so elegantly

any of the 3 measurments can be variable.
or vice versa.
any of the 3 variables can be measured.
----rusty