"operator jay" wrote:
"Floyd L. Davidson" wrote:

Picture my flashlight, battery powered. Generally this is considered a dc
circuit. When I turn it on or off, there is 'change'.

You were doing pretty good up to that point.

So is it in fact an
AC flashlight?

No. But that doesn't mean there is never any AC present in the
circuit.

It happens that with a battery powered flashlight that is rare
(but predictable too), and of no consequence whatever. It can
be ignored in design and operation of the flashlight. But that
doesn't mean there is never any AC in the circuit, or that there
are no circuits where it is significant.

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.

Every time you flip the switch on or off, there is AC in that
circuit.

You can probably prove it too, relatively easy. Tune an AM
receiver to a frequency where no station is being received, and
hold the flashlight up close to the antenna. Flip it on and off
a few times. I suspect, though I haven't actually tried this,
that you'll hear a pop in the radio's speaker almost every time
you flip the switch. That is because some of the AC produced by
flipping that switch is RF.

On another note, how long are the days getting to be way up there? Do you
get continuous sunshine?

It's been 24 hours of daylight for quite some time now. The sun
hasn't actually gone down for a month (May 10th), but of course
we had 24 hours of light long before that. The next time it
gets below the horizon will be August 1, and it will be late
August before it gets "dark".

The temperature is 30F right now, with a reported 18 mph wind and
fog. It was gusting up to 30 mph last night. It probably won't get
much warmer than maybe 36F today.

That is actually very comfortable weather, mostly because it is
unlikely to rain. I hate getting wet... :-)


--
Floyd L. Davidson http://web.newsguy.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)