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Re: dc/ac nomenclature

This morning I participated at an informal meeting of a
small group of active researchers at BNL (Brookhaven
National Laboratory); it is my summer project.

The terms ac and dc were used to distinguish signals,
not currents. In this particular situation it was the light
intensity versus time. Rapidly changing intensity was
called the ac signal while practically constant intensity
was called the dc signal. Nobody was confused. The
scope has two inputs, one labeled ac and another
labeled dc. That is likely to be the origin of the jargon.
Ludwik Kowalski

"Carl E. Mungan" wrote:

Three quick points of nomenclature about which I'd like to hear the
opinions of the list:

(1) Do you use "dc" and "constant current" as synonyms or not? eg. Is
I0*exp(-t/T) direct, since it never reverses direction? If so, the
sum of two dc values is not in general dc. That seems odd to me, but
if's that the accepted convention I can live with it.

(2) In light of your answer to (1), what does the term "quasi-dc" mean?

(3) Do you use "ac" to refer to things like voltage and the like
which are not currents?
--
Carl E. Mungan, Asst. Prof. of Physics 410-293-6680 (O) -3729 (F)
U.S. Naval Academy, Stop 9C, Annapolis, MD 21402-5026
mungan@usna.edu http://physics.usna.edu/physics/faculty/mungan/