Re: stun gun
Sokrat, glad the information is of some use
Sorry about not taking the easy route and posting a nice schem, but you know, someone could become a member, get the schem, build it, and either seriously hurt themselves, or someone else. I don't want to have that responsibility.
I did make a mistake with the maths. Its 25kW per pulse, but there are 10 pulses per second. So the total energy, per second is, 10*25000(W) * 0.00002 (S) = 5W.
And the current draw from a 9v PP3 battery would probably be about 600-800mA.
The 'pulsing' design that I described is the most complicated (still pretty simple) but apparently yeilds the best results. And its output power is easily controlled by changing values, like the main HV cap. As I said, its really split into two sections:
1) High voltage inverter. To get 9V up to 300-400V easily, you could use a mains transformer, in reverse. I've got 500V out of a 240V to 6-0-6V cheap mains transformer. Using a single transistor that switches one side of the primary to ground, with the centre tap of it connected to VCC. The other side of the primary is connected to the input of a simple voltage divider (10:1), with the output of the VD to the base of the transistor. So, one transistor, and two resistors are all you need to get 400-odd volts AC out from the secondary of the transformer. Rectify with a diode bridge, and maybe use a series resistor to reduce the voltage down to decent value. (since the above configuration, albeit simple, can produce spikes of about a thousand volts very efficiently, because its in resonsance).
2) Discharge section. Now you've got 400V DC (or pulsed DC) you charge your cap with the primary of another transformer in series with it. And for simplicity, a spark gap across you HV supply. As the cap charges, the voltage accross it rises, untill it reaches the breakdown voltage of the air gap (0.5mm?). When this fires, it completes the circuit, dumping all the cap energy intot he transformer primary. Producing a rather angry, fat, arc.
I mean by "stungun" a nasty shock thats meant to just 'put someone off'
Ahh, in that case, it *may* be easier to make a small cheap inverter. But the output of this cannot be so easily controlled. I've been zapped by a 3kV supply, at 2mA, and let me tell you that 'put me off'
To keep it safe, you could use a small audio transformer (600 ohm primary, the 1-2Kohm secondary) and feed ing with a 555 timer, controlling a MOSFET. Then, maybe a 'cockroft-walton' multiplier. If you don't know about this, google will have many answers.
That could make little 5 mm arcs, but at DC. Loud and quite intimidating. But prolonged use will burn. You could vary its power by changing the frequency of the 555 timer. OR.....if you're really into electronics
use a PIC micro to control the PWM going into the transformer. Maybe with feedback from the transformer output going into the PIC (via a divider network) so you can controll the output very accurately, and program in various pulse patterns. (putting digital controll on high voltage really is a wonderful thing)
OK, now I'm just ranting
Good luck. And if you get stuck, or have any questions, PM me.
BuriedCode.