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From: atn@cory.Berkeley.EDU (Alan Nishioka)
Newsgroups: sci.electronics
Subject: Are switches supposed to spark?
Message-ID: <27155@pasteur.Berkeley.EDU>
Date: 22 Aug 90 01:22:54 GMT
Sender: news@pasteur.Berkeley.EDU
Reply-To: atn@cory.Berkeley.EDU (Alan Nishioka)
Organization: University of California, Berkeley
Lines: 19


Are switches supposed to spark when you switch them?  Usually they have
opaque cases so I can't tell if they are sparking.

I just took apart a vacuum cleaner switch which had failed by fusing two
of the contacts together.  I separated them and put the switch back
together, and the switch worked, but the case is translucent and I can see
it spark when I switch the vacuum off.

Horowitz and Hill in The Art of Electronics show a "snubber" circuit
for use with inductive circuits, a 100 ohm resistor in series with a 0.05uF
capacitor, the combination in parallel with the load.  But they don't
mention why they chose those values.

Should I add something like this to the vacuum?  It's probably no big
deal, but I don't like to leave loose ends and I have a feeling if I
leave it, it will simply fail in the same way again.
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Alan Nishioka      KC6KHV      atn@cory.berkeley.edu      ...!ucbvax!cory!atn