[Avodah] electricity on shabbat

[Micha Berger]

On Tue, Jan 05, 2010 at 07:59:17PM +0200, Eli Turkel wrote:
:> Second, anything that almost inevitably sparks, even lo nikha lei, would
:> be bishul. That would include AC switches, many motors, etc...>>

: Let me quote from the article of Rabbi Broyde and Jachter in J Halacha
: Contemporary Society vol 21

: A Number of factorsindicate  that this prohibition is inaaplicable to sparks
: created by turning mechanical switches on or off. First these are
: created unintentionally
: davar sheno mitkaven - no prohibition exists since it is not psik reisha.
...
: Second the sparks are so small that one canot dtetect any heat when
: touching them and are usually not visible. Solid state technologies
: and sparkless (arcless) switches frequently avoid the problem completely.

Notice that I wrote about "almost inevitably sparks". To which I will
add, visibly, if you could see inside the switch's casing. This is my
understanding of what happens inside a regular light switch. 110 volts
(lo kol shekein 220) is enough to throw a significant spark across air --
just think of what happens with a loose wire almost properly in a socket.

The switch goes from too far to touching -- at some point along the way,
you will certainly have an air gap that can be crossed by visible
amounts of current.

We discussed this in Elecrodynamics, when I studied for my MS in
Electrical Engineering.

IOW, I don't understand the metzi'us to be as RMS and RJJ describe it.
My opinion is informed enough for me not to assume they necessarily
consulted with someone who knows the topic better than the education my
parents bought.

I read many teshuvos that assume that flourescent bulbs pose less of a
Shabbos problem. In practice, a florescent bulb has two filaments rather
than the one in an incandescent one (assuming it's not a three-way bulb
on the brightest setting). And unlike an incadescent, where the cooking
of the metal is a bad thing -- it leads to the bulb blowing, here we
boil something we need boiled -- mercury. If gakheles shel matekhes is
bishul, that too makes the florescent bulb *more* problematic. Once I
found error on the electonics of one question, I have grown skeptical
about the quality of the expert consulted in general. (I picture the
poseiq asking the electrician in his qehillah, rather than someone who
studied the theory.)

: So RSZA states that lehalacha there isnt a rabbinic prohibition in the
: uninentional creation of sparks

Agian, this presumes that it's not close enough to inevitable to be
pesiq reishei. That has to be established. Where's RDBannet?

...
: I am not sure what constantly running means. In any case an electric fan
: that constantly runs would have no prohibition according to RSZA

Unless it's a brushless motor, it too sparks.

:> Fourth, a radio, MP3 player, cell phone or TV are possibly within the
:> gezeira against keli zemer, since they're adjustable and can play music.

: A cell phone is kli zemer? far fetched - thats not its usual function.

RZS argued similarly. All I know is that people do download ringtones even
for the simplest cell phones -- never mind one that also has MP3 player
functions.

Laptops as well are regularly used to hold MP3 collections, watch concert
snippets on YouTube, etc... In the past few years they make a point of
having stereo.

: Listening to
: a speech on radio or a fotball game on TV would probably also not be kle zemer.

You're switching from noun to verb. The keli is a keli zemer since a
usual use is for music. At least, that's what I'm arguing. The maaseh
you want it for may not be zemer, but the cheftzah was already prohibited.

Tir'u baTov!
-Micha

-- 
Micha Berger             It is our choices...that show what we truly are,
micha at aishdas.org        far more than our abilities.
http://www.aishdas.org                           - J. K. Rowling
Fax: (270) 514-1507