[sdiy] Interesting DIY project...

[Scott Gravenhorst]

I remember building something similar as a kid, although it was not
powered by the mains at all.

It was a Hartley oscillator built using a power transistor (2N3055 I
think) and a 6.3 volt filament transformer.  The output was about 65
volts and pulsed at a rather low frequency, may 10 Hertz.  It was
powered by 2 C batteries in series.  The project was published in
Popular Electronics as "The Tickle Stick", which was a plastic or
carboard tube with the electronics inside.  Two foil electrodes were
glued to the outside and connected to the xfmr primary (well, what is
normally the primary).

I took this in a slightly different direction.  I got hold of an empty
mixed nuts can and wrapped scotch tape around the top edge so that when
the lid is on, the lid and can are insulated from each other.  The
output leads were then soldered to the can and top.  There was a 1/8"
switched jack in the bottom, inserting a plug turned the unit off.  It
was great fun passing around my 8th grade class room.  The eventual
disruptive noise from a student not aware of what it was and attracted
the teacher's attention.  Of course, he (my SCIENCE teacher) took it
away from that student.  Later, while we were studying, the teacher
opened the can to see what was inside.  He started poking about inside
with a pair of metal uninsulated scissors and he must have hit something
hot because his hand and the scissors went flying.  The scissors landed
several yards behind him.  After that, he put the top on it and handed
it back to me saying "don't bring this back here."

It was a very fun day!

harrybissell <harrybissell at prodigy.net> wrote:
>Wow... that is TRULY fvcking crazy.  That circuit WILL kill you if
>anything
>goes wrong - literally you are trusting your like to three resistors !
>
>At least, they should have added an mains isolation transformer.
>
>What happens if the person touches the knob and another earth ground...
>and
>the phases happened to be reversed ?   Where are the "three 10K
>resistors for
>safety" then.
>
>dumb, dumb, DUMB !!!
> (so don't do this)
>
>H^) harry
>
>Jay wrote:
>
>> http://www.emanator.demon.co.uk/bigclive/tickle.htm
>

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