On Sat, 07 Aug 2004 15:58:33 +0200, Juergen Hannappel
wrote:

Vacuum pumps? I have never seen any vacuum pump which was switched of
when the desired vacuum level was reached,

That's because you're posting from a physics lab, with real pumps. If
you're using something like a Gast diaphram pump, or even worse an old
fridge compressor, then it's useful to switch it.

--
Smert' spamionam