"Kitchen Man" wrote in message
...
On Sun, 12 Jun 2005 22:59:18 -0500, "operator jay"
wrote:

You are the one with the requirements, assertions, and definitions, not
me.

Actually, the ones with the requirements, assertions, and definitions
are codes and organizations such as the NEC and the IEEE, and the
bothersome universities that teach the stuff.

If you have definitions of AC and DC handy from IEEE or someone, stick them
on here. I'd say that the (apparent) widespread disagreement means that,
functionally, there is no single pervasive definition for these terms, but
it would be interesting to see if some of these bodies have published
definitions. It would be really interesting if they had definitions, and
they didn't quite agree with one another, or if they were "wishy-washy".


On this point:

Picture my flashlight, battery powered. Generally this is considered a
dc
circuit. When I turn it on or off, there is 'change'. So is it in fact
an
AC flashlight? If the battery starts to die there is a change so is it
in
fact an AC battery? Etcetera. (These questions are rhetorical by the
way).
I know better than to try to pin a strict name on these things where
there
is not an (adequately) universal and strict definition.

You are talking about transients, and if you intend for the questions
to be rhetorical, then I think you should demonstrate some expertise
in the subject matter that shows why the questions' answers must be
obvious. I don't think they are, so I will answer the questions:

"show why the answers must be obvious" sounds like a peculiar concept. An
obvious answer inherently needs no explaining.


The behavior of the flashlight in your example is neither AC nor DC,
it is transient. The first case is the instantaneous step function
caused by the closing of a source to a circuit. The second case is a
long-term curved ramp caused by the decay of a voltage source. AC and
DC analyses are steady-state. AC analysis will never apply to the
example. DC analysis must be performed prior to the transient
analysis in order to provide a steady state model for the application
of time-sensitive mathematics.

You feel that neither AC nor DC is correct as a description for the
flashlight behavior. I wonder whether there is a sufficiently definitive
(and also agreeable) meaning of "AC" or of "DC" that would merit this
position. I infer from other posts that there are people who would say it
is DC. There may be others who would say it is AC. So a statement of fact
that it is neither AC nor DC is suspect. By the way, my rhetorical
questions were actually whether it is an AC flashlight and whether it is an
AC battery. The point of this was (I thought obviously) to illuminate the
difficulty in declaring some things to be AC or to be DC. There is a
certain ridiculousness (I thought obviously) in calling a flashlight AC or
in calling a battery AC. Yet it would be awkward (I thought obviously) in
adhering to calling it DC if one's description of DC was that the (voltage /
current) would essentially remain constant. Thus my (possibly obvious)
point and my rhetoricals. I'll work on them. Your response did not seem to
conradict my point.


There is quite a bit of information available on the web about circuit
analysis. Your curiosity is to be commended; you might consider a web
crawling adventure, or even an education in the field.

The web has lots of information and lots of misinformation, I think you'd
agree. I'm not sure that I have displayed curiosity in these posts. An
education in the field of circuit analysis? No, thanks, you go ahead.


And hey operator jay, what do you operate? Not electrical
substations, I wouldn't guess.


That's remarkably funny. What do you operate? Not your brain I wouldn't
guess.

j