Some questions on terminology (for native English speakers)

[vopros217]

Hello! I am a beginner in English terminology.
I know that direct current is a flow of electricity that moves in one direction only (i.e. does not change its direction).
I also know that alternating current is an electric current that reverses direction at regular intervals.

However, I cannot find in my dictionaries the proper English terms for:
1) a DC current, which does not change its intensity at all,
2) a current, which does change its intensity, but not necessarily its direction (that is, the general term for AC, pulsating DC, DC smoothly petering out etc.)

I find several word combinations, which may or may not be the right terms:
1) steady current, constant current, time-independent current, stationary current;
2) time-dependent current, time-varying current, variable current.

Which are the standard (conventional) terms, OK but awkward terms and wrong (misleading) terms?
Is there any authoritative source in English (a textbook, an encyclopedia, a standard etc.) which I can quote when discussing these terms with my compatriots?

If you don't know the standard names, what do YOU call these currents?

 

[Simon Bridge]

However, I cannot find in my dictionaries the proper English terms for:
1) a DC current, which does not change its intensity at all,[/quote]
this is called a steady or constant current. It is given a capitol I for it's symbol.

2) a current, which does change its intensity, but not necessarily its direction (that is, the general term for AC, pulsating DC, DC smoothly petering out etc.)

this is called a varying current. It is given a lower case i of i(t) to show it changes with time.

I find several word combinations, which may or may not be the right terms:
1) steady current, constant current, time-independent current, stationary current;
2) time-dependent current, time-varying current, variable current.

These are all acceptable - any English speaker who knows electronics will understand what you mean.

Is there any authoritative source in English (a textbook, an encyclopedia, a standard etc.) which I can quote when discussing these terms with my compatriots?

Any English language textbook will do.

 

[tech99]

However, I cannot find in my dictionaries the proper English terms for:
1) a DC current, which does not change its intensity at all,
2) a current, which does change its intensity, but not necessarily its direction (that is, the general term for AC, pulsating DC, DC smoothly petering out etc.)

I find several word combinations, which may or may not be the right terms:
1) steady current, constant current, time-independent current, stationary current;
2) time-dependent current, time-varying current, variable current.

I would suggest,
(1) A steady current
(2) A varying current

 

[jim hardy]

We English speakers are not consistent, you'll find the terms often used loosely.

I like Simon's post.

Think of it as a hierarchy
Direct means as you said unidirectional. But that does not preclude variations.
This would be Direct Current as it's unidirectional

(okay it's voltage, but current through the resistor has same shape)

This is approaching "steady"

I'd call it DC with Ripple and put a number on the peak to peak ripple as % of average

and at some point where the ripple ibecomes insignificant to the task at hand it'd be okay to call it "steady"
and that point is up to the author, or the person explaining it.
In most but not all applications 0.1% ripple is negligible .

If the graph is an absolutely straight line as from a battery it's steady, unquestionably, and also direct.
If it's well enough filtered and regulated it might as well be called steady even though with a big enough microscope you can see variations

poorly filtered or unfiltered as first picture it's direct but not steady.



Any help ?

old jim