brandon

yeah hi, im new to the site so ill start off by saying hello. ive got a project going at the moment regarding a shcematic i found on the net of a 'stungun' my main problem is being able to locate the transformer ,the one in question is called the lt44 it has a centre tapped winding of 1k on primary and 20k on secondary i can not find were to order these suckers anywere also is it possible to increase the output by using a higher rated transformer say like 1kct-200k? or if i use 2 9volts in series or parrallel ?,or could i lengthen the bank of capacitors on the end to get a higher rated output thankyou for your time,Brandon :?

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pike

yeah you could lenthen the bank of capacitors but your gonna have to find higher rated parts to handle the increased voltage.

BTW: where did you find the 200:1 transformer, i can't find these in Sydney anywhere????

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Nigel Goodwin

An LT44 is a very standard audio driver transformer, but is a very old part now - probably early 1970's, if not 1960's.

Maplin still list them in the UK, have a look at http://www.maplin.co.uk and order code HX82D.

The diagram doesn't make much sense - the output is labelled 30KV/8A!.

That's 240,000W of power 8)

I suspect 8uA would be more likely.

brandon

yeah ive had a hard time tracking down the lt44 1k-20k one of the only places ive found that sells them is tandy electronics and sadly enough there only available trough there telephone amplifier kit not as a seperate item im waiting on reply to other companies that might stock them seperatly,as the lt44 is rated at 1k-20k will it up the output if i change the transformer to 1k-200k??

Nigel Goodwin

Yes, by a factor of ten! - or five if you use the full 1K, the original design only uses half of the input winding. This would probably require all the parts in the Walton-Cockcroft multiplier uprating as well.

mechie

The LT44 spec sheet states that it's IMPEDANCE is
. . . 1k0 Ohms (centre tapped) to 20k Ohms

I can find no refrence to its WINDING RATIO

The latter is the figure that will define your step - up ratio, the impedance will have more effect on output power than voltage.
Has anybody tried a tiny mains transformer (240v to 3v or similar), wired backwards this should give some 240/3 = 80v out for the multiplier to work with;
A four stage multiplier could then give 1kV ?

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I find it amazing how popular these "stun gun" circuits are and yet no-one ever seems to report their results in anything other than anecdotal form. Has ANYONE actually measured their circuit's output.

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grrr_arrghh

isn't that a 20K primary and 1K secondary?

wouldn't that only give you 180V - surely you wouldn't even feel that...?

Nigel Goodwin

The circuit only uses half the 1K winding, so it will give about 360V from the transformer, but you would feel 180V anyway.

But that's not the final voltage, the 360V AC is fed through a Walton-Cockcroft multiplier, which builds the voltage up - the amount depending on the number of stages, and producing a DC voltage at the output.