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More Bang For The Buck?

I'm interested in seeing how well magnetostrictive metals like nickel work as transducers and I got the idea to use a cheapie electronic flash unit to send a high voltage pulse into a coil of wire (of unknown impedance) surrounding either a nickel rod or ring.

It's been a real long time since I've played with flash circuits or built them, and I think I'm forgetting something somewhere along the way. Does anyone know of a way for me to get my energy pulse without destroying the flash unit on the first go? Or would the flash unit be able to handle what amounts to be a direct short without any problems? Any information would be appreciated.

Ron

-- "You see me now a veteran, of a thousand psychic wars. I've been living on the edge so long where the winds of limbo roar."

Reply to
Ron Hubbard
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Use Terfenol-D

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
Reply to
Dirk Bruere at Neopax

If you know what the peak current through the xenon bulb that the flash circuit uses will be, then it is a matter of having enough inductance in the coil to stay below that value when the capacitor has dumped all the energy into the coil.

It is probaly also good to have a free-wheeling diode on the coil so the electrolytic capacitor does not have to take the reverse voltage. Not an

1N4001 - a real switching diode with proper ratings.
Reply to
Frithiof Andreas Jensen

wire

be

problems?

Hi, Dirk;

Would you happen to know a supplier?

Ron

Reply to
Ron Hubbard

wire

be

problems?

flash

in the

energy

the

an

Thanks for the tip about the diode; it's something I wouldn't have thought about. But I'm not quite sure what you mean about the coil's inductance.

Ron

Reply to
Ron Hubbard

Not offhand. I got some a few years ago from a company making transducers. However, it's expensive stuff but very efficient. Conversion of electric to mech can hit 50%.

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
Reply to
Dirk Bruere at Neopax

That what you are building is an L-C circuit with "the load" in parallel.

Assuming nothing in the coil, not even resistance, All the energy in the capacitor will transfer to to the coil and be stored in the magnetic field. The current will be given by the energy in the capacitor, which is Ecap =

1/2CV^2 transferred to the coil as Ecoil=1/2LI^2.

Increasing the Inductance, L, by putting on more windings, and/or making the coil bigger, lowers the peak current - because the Energy stays the same.

The thyristor in the flash unit must endure the I^2 of this current - and it will be in the data sheet for the SCR - as well as the Peak Current which will also be in the data sheet. If you keep the peak below whatever the Flash tube takes, it should be fine.

Introducing your material in the coil will increase the peak current by an amount that is best measured by experiment. Think of it as a load in parallel to the coil.

Reply to
Frithiof Andreas Jensen

parallel.

the

field.

Ecap =

making the

same.

and it

which

the

by an

I get it now. Many thanks!

Ron

Reply to
Ron Hubbard

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