OHM

Status
Not open for further replies.

throbscottle

Well-Known Member
Ohm for goodness sake...

schmitt trigger

Well-Known Member
There is a website, which for the life of me I cannot find anymore, which has many of science related funny cartoons.

Grossel

Well-Known Member
In my languages the "om" word is "about" in english, so when talking about "ohm" - sounds very strange (to talking about a(h)bout) . . .

throbscottle

Well-Known Member
English is a confusing language even for English speakers, so I don't envy your position!

gophert

Well-Known Member
I wish the "ohm" unit of measurement was never introduced. It's like the speed unit of Mach. Completely unhelpful to just have a speed term, or a resistance term unless you only need to compare speeds or compare resistances.

Speed is really a derivative term a change in distance over a change in time. It becomes very easy to do the math and intuitive to cancel units of measurement and appropriately multiply, divide and estimate changes when expressed as Distance/Time.

Ohm should be expressed for what it is, Volts/Amp.

Example, I have a 12 volt supply and an LED with Vf = 2 requiring 0.5 amps. How much current limiting do I need?
10V/0.5A=20V/A resistance. It becomes much easier to teach someone electrical concepts.

crutschow

Well-Known Member
I wish the "ohm" unit of measurement was never introduced.
That's a rather odd statement.
Any other terms you want to eliminate?
Someone else on these sites wants to eliminate the decibel.

gophert

Well-Known Member
That's a rather odd statement.
Any other terms you want to eliminate?
Someone else on these sites wants to eliminate the decibel.
Not an odd statement at all. Why do we use miles/hr? Why don't we rename it to the Ford, or the Stanley or anyone else associated with car or train travel to commemorate what made this unit of measure important to the English-speaking (and English measuring) world? Answer, because naming the derivative unit makes any estimate of changes to time or distance less obvious TO THOSE NOT USING THE UNITS ON A DAILY BASIS. Have some empathy, think about a student leaning for the first time instead of your own view after a 25-year to 40-year history with the term.

Decibel has been a clear target by many for a long time. But decibel is specifically designed to compare two measurements of the same unit (like Mach speed). Decibel is not so easy when you want to make calculations of the inputs so you immediately jump to volts or power before converting back to decibels again. Again, think of a new student instead of your career.
Note that one member used to have his signature line that read something like, "eliminate the decibel" long before you mentioned it.
Finally, referring to resistance as volts/amp doesn't get rid of ohm's law, it just avoids an unnecessary layer of abstraction. Call it what it is, volts per amp.

Last edited:

atferrari

Well-Known Member
I wish the "ohm" unit of measurement was never introduced. It's like the speed unit of Mach. Completely unhelpful to just have a speed term, or a resistance term unless you only need to compare speeds or compare resistances.

Speed is really a derivative term a change in distance over a change in time. It becomes very easy to do the math and intuitive to cancel units of measurement and appropriately multiply, divide and estimate changes when expressed as Distance/Time.

Ohm should be expressed for what it is, Volts/Amp.

Example, I have a 12 volt supply and an LED with Vf = 2 requiring 0.5 amps. How much current limiting do I need?
10V/0.5A=20V/A resistance. It becomes much easier to teach someone electrical concepts.
Is all this because you do not feel at ease with it, gophert?

Had you said that about the microsievert I would had agree because I use it once every ten years...and even then...

crutschow

Well-Known Member
referring to resistance as volts/amp doesn't get rid of ohm's law, it just avoids an unnecessary layer of abstraction
Well I think most prefer that extra layer.
So you would label resistors as volts/amp rather than ohms?
Seems a lot simpler to say I need a 10k ohm resistor compared to I need a 10k volts per amp resistor.

gophert

Well-Known Member
Well I think most prefer that extra layer.
So you would label resistors as volts/amp rather than ohms?
My resistors generally have color codes or abbreviated numeric codes on SMDs and don't specify "ohms". Which brand do you buy?

If you're talking schematics, even those are commonly just numeric or use the generalized "R" notation in most cases.

Seems a lot simpler to say I need a "10k ohm resistor" compared to I need a 10k volts per amp resistor.
It's even easier to say a 10k resistor.

If you're talking schematics, even those are commonly just numeric or use the generalized "R" notation in most cases. Which is even more evidence the word "ohm" can be eliminated. I've considered all of your "arguments" (love of tradition?/inability to deal with changes?) and more and I can't find a reason to use the word 'ohm'.

rjenkinsgb

Well-Known Member
"I want 10" 4 speaker"
A four speaker cabinet?
A 10" empty cab for your 10" speaker?

"I need a roll of 50 coaxial cable".
50ft? 50 metres? .5 inch?

I can think of numerous places a unit for resistance is explicitly required to avoid confusion.

gophert

Well-Known Member
"I want 10" 4 speaker"
A four speaker cabinet?
A 10" empty cab for your 10" speaker?

"I need a roll of 50 coaxial cable".
50ft? 50 metres? .5 inch?

I can think of numerous places a unit for resistance is explicitly required to avoid confusion.
and wouldn't a 8 volt/amp speaker make it easy to calculate the power if you have a +/-45v DC (~32VRMS max signal)?

crutschow

Well-Known Member
If you're talking schematics, even those are commonly just numeric or use the generalized "R" notation in most cases.
So since schematics do not need to use Farads for capacitor values or Henries for inductance values, then I suppose those can be eliminated also.

gophert

Well-Known Member
So since schematics do not need to use Farads for capacitor values or Henries for inductance values, then I suppose those can be eliminated also.
No. But they can if you want.
The capacitor symbol next to 100u is kind of a give away that the SI unit for the value is F. Or do you get confused.

rjenkinsgb

Well-Known Member
and wouldn't a 8 volt/amp speaker make it easy to calculate the power
As speakers (and many other things) use Ohms to represent impedance ?? No.

Try and order some 50 volt/amp coax!
Doh.

Nigel Goodwin

Super Moderator
As speakers (and many other things) use Ohms to represent impedance ?? No.

Try and order some 50 volt/amp coax!
Doh.
Yep - it's like he's trying for the most stupid posts ever!.

Status
Not open for further replies.