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Comment by jacquesm | Hacker News Reader

Pretty sparks!

As a kid I got my hands on a HV transformer from a rooftop light installation.

Two pieces of curved wires attached to the terminals, touch the base between the wires with a hammer and a spark would ride up the curve.

As soon as the spark extinguished that would temporarily excite the coil to an even higher voltage because of the circuit breaking, if you set it up just so that would be enough to jump the gap between the two wires at the bottom and the cycle would repeat.

Friggin' dangerous but lots of fun.

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Sounds like a Jacob's Ladder or some variant thereof. http://www.youtube.com/watch?v=qh-Tt09IC8M

My grandfather built one in his basement. It zapped him once and sent him clear across the room.

Ha, that reminded me of one of my heros: Michio Kaku. He built a particle accelerator in his basement when he was a teenager and wiped out every transformer in his neighbourhood! Another amazingly reckless Japanese guy who inspires from the danger of the edge (he now builds infinite improbability drives for the galactic elite).

"Got my hands on" is not the best expression to use when talking about electrical equipment :)

I managed to avoid that while it was switched on.

If my mom had known what I was up to with that thing it would have been gone in a heartbeat.

It's a small miracle I got this old anyway, considering the fact that I chopped the top of a BLX15 with a dremel to see what it looks like inside.

I was young, stupid and apparently very lucky.

Chopped the top off a what?

A BLX15 is a high frequency power transistor (well, what's high frequency, these days 150 MHz doesn't count for much I guess, but in the 80's it was hot shit), it is encased in a compound that has really good thermal conductivity.

One of the major components of that casing is Beryllium-Oxide.

http://en.wikipedia.org/wiki/Beryllium_oxide

Apparently it is entirely safe to handle, as long as you do not grind it to dust, which is exactly what I did, not wearing a respirator or any other safety measures, I never realized how dangerous that stuff was.

I was simply interested in seeing what the guts of a transistor like that looked like and the best way to do that without causing damage was to slowly grind the cap off.

Not a smart thing to do.

I only found out many years later. Fortunately I never had any Berylliosis symptoms so I think I got away clean.

Luck favours dumb people.

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