Therese no doubt gizmos like this work, the way I've seen it done is with a so-called audio output transformer which are commonly available at radio shlock.
these have two windings, the "primary" has several hundred turns at least whereas the secondary has relatively few turns. If you connect/disconnect a battery to the "secondary" momentarilly, the magnetic field building and collapsing in that small winding with induce a much higher voltage field in the "primary" which has many more turns. This can give a peak voltage of several hundred volts but with no real amount of current available, thus very little danger. I used to see a coffee can with a crank built up as a temptation to turn the crank which got you quite a noticable shock. Using a single coil will also work but probably with not as high an output spike. Tom Fowle On Thu, Dec 03, 2009 at 11:34:35PM -0500, John Sherrer wrote: > I was thinking of a solenoid coil used in washing machine to turn the water > on and off. They are cheap. I as also thinking that the voltage spike might > two or three thousand volts. The voltage spike occurs when the voltage > supply is turned on or off, but no spike when the coil has power or is off, > only when change happens is their a voltage spike. > A friend of mine, when I was a teenager had a book with an aluminum foil > cover. When you opened the book or cclosed the book, you got a little bite. > > John > http://WhiteCane.org > http://BlindWoodWorker.com > http://HolyTeaClub.comcom\whitecane > http://anellos.ws > > ----- Original Message ----- > From: Tom Fowle > To: blindhandyman@yahoogroups.com > Sent: Thursday, December 03, 2009 1:39 PM > Subject: Re: [BlindHandyMan] Inventors ahoy! > > > > John's ideas are interesting, that solenoid coil would have to have a lot of > turns on it, I'm not sure dogs responde to even moderate electric shocks > as much as humans do, I think they need say 600 volts or so to make them > take > notice. > > I like the meat tray and pans idea except it'll wak up everyone in > the house too. > > Maybe just a wireless baby monitor placed near the plate would give you > enough > sound to start yelling at him. > > What you don't want is false positives, if the thing goes off when it > shouldn't > the dog will quickly learn to ignore it because he doesn't know what it > means. > > Tom Fowle > > > > > > [Non-text portions of this message have been removed] >
