22 Aug
2006
22 Aug
'06
10:20 p.m.
On 8/22/2006 at 11:33 PM Roy J. Tellason wrote:
What sorts of stuff would you do with those ingredients
anyway?
"Make your own secondary cells" (H2SO4 and Pb)
"Low resistance contact switches" (Pool of mercury into which a a contact
is lowered
"Make your own voltage calibration source" (Weston or Clark cell)
Sometimes the old texts have very clever ideas. I have an old book on
building pipe organs with electrical key action. Power on/off was achieved
not through a switch, but by lowering and raising the electrodes of a bank
of wet Leclanche cells in and out of the electrolyte using a pneumatic
bellows.
The same text recommends winding electromagnets with insulated iron wire
rather than copper, to keep current draw down by virtue of iron's higher
resistance.
Cheers,
Chuck