DIY malicious stun gun
The circuit
It's time to see it. As i said before, the circuit is very simple. It's based on self-oscillating Royer-type converter. By the way, it's not very critical what circuit to use. This can be anything rated to deliver 10-15 watt output. What i like in this design - it's very flexible; you can get power range from 10 to 50 watt only by playing with power source, nothing else. Of course it's not very practical for other applications, because of bad thermal mode, hard to control frequency etc. But we're making a stun gun, which works in pulse mode, and this is not a problem at all.
Converter charges two capacitors which are separated with diode to prevent forming one ciruit. This is done to simplify overall design; in the other case we need standalone transformer winding and second FW bridge. More parts, more complications... So i think one diode is much better for practical usage ;-) This leads to only one limitation: the capacitors must be of the same type and value. I think this isn't very critical too ;-)
The thing labeled "1400v" is a surge arrester. This is a gas filled spark gap, small cylinder shape thing with two leads. It's manufactured by several companies like EPCOS, CITEL, BOURNS and others. I suggest to buy exact type as specified in parts list. Operation of entire device depends mainly on surge arrester and capacitors, so choose carefully, "just any cap" will not work or even blow instead! All other parts can be of any type. You can use wide range of MOSFET's from IRFZ24 to IRL2505 or just any other that will handle required power level. 3300 cap limits the initial current pulse at the start of charging. It's not required and can be safely excluded from the circuit, if you have enough powerful transistors, like IRFZ44 and better.
You may have noticed, that here's one interesting issue with ciruit operation. If you short the output, the second capacitor will not be in time to charge; the frequency of pulse repetition will rise and device becomes a "shit rattle" :-( This can happen in case of direct contact of both terminals with opponent skin. However, this is not critical because capacitor voltage is only 1000 volts, what is insufflicent to break even a thin vest. But if you are definately going to start a war with nudists :-D YOU SHOULD USE A SECOND ARRESTER of the same value in series with any of output terminals!
Few words about actual construction. Entire circuit fits on 40*45mm PCB. The power source is six sub-AA 300mA/h NiCd batteries. They are sold in blocks of 3 or 4 as replacement for old cordless phones. These are low cost ones. They give about 15 watts of output power. You can either buy professional batteries used in hobby aircraft modelling. They have much higher capacity and current output. With this sub-type batteries entire device can be fit into a size if cigarette box. Of course other types are allowed; you can use AA, C, D or even place car battery inside a backpack and wear it :D But do you need a weapon or a toy to play?
Now take a heatsink and install transistors on it. You should isolate them from the surface, or either use two separate heatsinks. The initial assembly is recommended without pcb for testing and debugging purposes :-) Output leads should be placed close, say 1/2" for beginning.
Now turn in on. IMPORTANT! While testing, use exactly the same power source you plain to use in final construction! It should start working immediately. With 6 NiCd's repetition rate will be about 35 per second. If it's much less you should check out the transformer, or pick up the correct value of "330" resistors to match your MOSFET's. Look into the datasheet and find "INPUT CAPACITANCE" value. The more it is, the less resistor value should be, and vice versa. In example, for IRFZ44 it can be up to 1k, and for IRL2505 it should be lower than 240 Ohms.
When the output in tuned, you can increase the distance between terminals, but consider that final distance must be at least 1/3" less than maximum available from the transformer. Actual spark distance vs voltage depends on many factors like air humidity, pressure etc. So you need some reserve for safe operation.
Now, if everything works well proceed to the next section...
It's time to see it. As i said before, the circuit is very simple. It's based on self-oscillating Royer-type converter. By the way, it's not very critical what circuit to use. This can be anything rated to deliver 10-15 watt output. What i like in this design - it's very flexible; you can get power range from 10 to 50 watt only by playing with power source, nothing else. Of course it's not very practical for other applications, because of bad thermal mode, hard to control frequency etc. But we're making a stun gun, which works in pulse mode, and this is not a problem at all.
Converter charges two capacitors which are separated with diode to prevent forming one ciruit. This is done to simplify overall design; in the other case we need standalone transformer winding and second FW bridge. More parts, more complications... So i think one diode is much better for practical usage ;-) This leads to only one limitation: the capacitors must be of the same type and value. I think this isn't very critical too ;-)
The thing labeled "1400v" is a surge arrester. This is a gas filled spark gap, small cylinder shape thing with two leads. It's manufactured by several companies like EPCOS, CITEL, BOURNS and others. I suggest to buy exact type as specified in parts list. Operation of entire device depends mainly on surge arrester and capacitors, so choose carefully, "just any cap" will not work or even blow instead! All other parts can be of any type. You can use wide range of MOSFET's from IRFZ24 to IRL2505 or just any other that will handle required power level. 3300 cap limits the initial current pulse at the start of charging. It's not required and can be safely excluded from the circuit, if you have enough powerful transistors, like IRFZ44 and better.
You may have noticed, that here's one interesting issue with ciruit operation. If you short the output, the second capacitor will not be in time to charge; the frequency of pulse repetition will rise and device becomes a "shit rattle" :-( This can happen in case of direct contact of both terminals with opponent skin. However, this is not critical because capacitor voltage is only 1000 volts, what is insufflicent to break even a thin vest. But if you are definately going to start a war with nudists :-D YOU SHOULD USE A SECOND ARRESTER of the same value in series with any of output terminals!
Few words about actual construction. Entire circuit fits on 40*45mm PCB. The power source is six sub-AA 300mA/h NiCd batteries. They are sold in blocks of 3 or 4 as replacement for old cordless phones. These are low cost ones. They give about 15 watts of output power. You can either buy professional batteries used in hobby aircraft modelling. They have much higher capacity and current output. With this sub-type batteries entire device can be fit into a size if cigarette box. Of course other types are allowed; you can use AA, C, D or even place car battery inside a backpack and wear it :D But do you need a weapon or a toy to play?
Now take a heatsink and install transistors on it. You should isolate them from the surface, or either use two separate heatsinks. The initial assembly is recommended without pcb for testing and debugging purposes :-) Output leads should be placed close, say 1/2" for beginning.
Now turn in on. IMPORTANT! While testing, use exactly the same power source you plain to use in final construction! It should start working immediately. With 6 NiCd's repetition rate will be about 35 per second. If it's much less you should check out the transformer, or pick up the correct value of "330" resistors to match your MOSFET's. Look into the datasheet and find "INPUT CAPACITANCE" value. The more it is, the less resistor value should be, and vice versa. In example, for IRFZ44 it can be up to 1k, and for IRL2505 it should be lower than 240 Ohms.
When the output in tuned, you can increase the distance between terminals, but consider that final distance must be at least 1/3" less than maximum available from the transformer. Actual spark distance vs voltage depends on many factors like air humidity, pressure etc. So you need some reserve for safe operation.
Now, if everything works well proceed to the next section...
Захуярил 