Assume v. Presume

MikeSh

Well-Known Member
So the team think we should use D current or A current, and presumably D voltage and A voltage?

I don't actually think DC of AC current is wrong, but as an electrical engineer I have been brainwashed I suppose. Direct Current and Alternating Current are classes of circuit and the terms are used as adjectives for various nouns of which one happens to be current. Should that be changed just for the one case?
And there are other examples like LV voltage ...
 
OP
Black Hole

Black Hole

May contain traces of nut
I acknowledge AC/DC current/voltage are common usage, but surely you're not disagreeing they are a tautology (or an contradiction, in the case of AC/DC voltage)?
 

Trev

The Dumb One
Yep. How stupid of me in AvP.
It's almost as bad as when equally stupid people refer to their card's PIN number. Now, hands up anyone who hasn't done that. :duel:
 

MikeSh

Well-Known Member
Tautology - definitely.
I'm not so sure. I feel the word 'current' has a subtly different meaning in the two instances. DC or AC is referring to the general type of supply, which harks back to when these things were first invented/discovered/generated, and is thus a bit Victorian. If starting today we might well choose a different vocabulary.

The reference to DC or AC "current" is specifically meaning the amount of Amps/mA that is being passed.

Like many English words 'current' has a number of meanings. To me "The current DC current is 3 Amps" is fine.
 

Trev

The Dumb One
3A DC also works for me.
What about 3V DC. Now we are mixing Volts and Amps. That's Watts in my book.
 

Trev

The Dumb One
It cant be that. Algebraically, XY is X times Y, so in my example it's 3V times an unknown magnitude of direct current = Watts
 

gomezz

Well-Known Member
3A DC also works for me.
What about 3V DC. Now we are mixing Volts and Amps. That's Watts in my book.
5V DC is what I look for in a USB power supply, usually in the 500mA to 2.2V range (not up to date with what USB-C can offer).
 
OP
Black Hole

Black Hole

May contain traces of nut
Like many English words 'current' has a number of meanings. To me "The current DC current is 3 Amps" is fine.
3A DC also works for me.
Yeah, and "dish" to describe the complete assembly at the top end of the cable connected to a satellite TV receiver works for me.

What works isn't the point; it's still tautology (so are "PIN number", "RAS Syndrome" [deliberate]).
 

MikeSh

Well-Known Member
(and I don't like the "s" on the end of units).
How strange. What is the genesis of that idea?

(Most if not all units are defined by the size of one of them (eg. 1 mile = 1760 yards), so if you have more than one they are plural.)
 
OP
Black Hole

Black Hole

May contain traces of nut
and I don't like the "s" on the end of units
How strange. What is the genesis of that idea?
Indeed. Amp is short for Ampere, you certainly wouldn't use the singular form unless it was exactly one, so it's 3 Amps.

Can't be Ohms as the two 'quantities are multiplied algebraically as I stated above.
What?

You're the only one who said anything about multiplying volts and amps, the first mention said "mixing", which could just as well be a division and therefore ohms or siemens (don't go there!).
 
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