dstich

i am looking at buliding a stun gun but i have a couple of questions how do the stun guns keep the amps so low i thought a biger capaciter ment more amps so how do the stun guns that can diliver a sustaned discharge keep the amps from going up and do resisters lower voltage and amps or just apms

magickaldan

Well Most Stun Guns don't have big capacitors. They have small capacitors about the size of camera capacitors. They have something to charge to capacitor to around probably 110v then it discharges through a High Voltage Transformer which steps the voltage up to a very HIGH voltage, and the current down to safer levers around 35mA to paralyze muscles.
Edit:
To Store 1 Amp of Charge Requires a 1 Farad Capacitor, and thats about the size of a tuna can. Well if you goto http://www.howstuffworks.com/ and search capacitors it tells you a great deal more about them.

Phasor

I don't think you quite have the right idea there. Firstly, some terminology problems: "Charge" is not measured in amps. Charge is measured in Coulombs. The Ampere (amp) is a RATE of flow of charge, equivalent to 1 Coulomb per second.

Any capacitor can store 1 Coulomb (or any amount of charge, for that matter), provided you charge it to a high enough voltage (and that the capacitor is rated to withstand that voltage). This is reflected in the equation:

Q = CV
where Q is charge (in Coulombs), C is the capacitance (in Farads) and V is the voltage across the capacitor.

The maximum CURRENT that a capacitor can deliver is determined by its ESR (Equivalent Series Resistance), or as some like to think of it, Internal Resistance. So you don't need a 1F capacitor, to deliver 1A.

Does this clear things up a bit?

EDIT: Forgot to mention before, that the traditional definition of a Farad, is the capacitance which causes the voltage to increase by 1V, when a current of 1A is applied for 1 second. ie, 1 F = 1 As/V

dstich

i thouught that 35ma would kill you at 600 volts i looked at the circit im buliding it dosent store the charge in a cap it just runs it threw a transformer then thew a couple voltage doublers but i do have a transformer q how do you tell how much it step up the voltage and about voltage doublers and tranformers how do you tell how much it will lower the curent and do resisters lower voltage or just curent

chemelec

All of those Sun Guns that just use a Diode Multiplier are not Really true stun guns. They produce a relatively low voltage (Maybe 1800 volts) that requires Direct contact with the persons skin and they only deliver a VERY LOW CURRENT, typically in the Micro-Amp region.

Commerical Stun Guns deliver High Voltages 50KV or Greater and relatively higher currents in the Ma Region.
Additionally they have an Arc to give a Threatning Warning sound, But that Arc also Limits and Protects the output Transformer from Excessive voltages that will cause it to short out.

A couple of examples of reasonably good stun guns can be found on my site at:
http://www3.telus.net/chemelec/Projects/Projects.htm

Biggest Problem is Winding and INSULATING the Output Transformer.

Take care......Gary

magickaldan

Actually its around 70mA for 1 sec that can kill you. Around 10mA will give great pain and 15mA will cause Loss of muscle control.
And on average the skin resistance is 100,000 ohms
and at 600v only 0.006Amps would get through. So more like static shock. Unless your wet or have oily skin and stuff like that. About 1Amp can get through your skin on commercial 100kV stun guns. So you want relatively high voltage.

Nigel Goodwin

That's all very well in theory, but the current available from any stun gun is far, far less than that - 100KW from a handheld device, I don't think so 8)

Also, skin resistance varies widely between different people, and (as you mentioned) due to variations in skin conditions - when it's warm and you're sweating it's comes down drastically.

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