I have a question about the stun gun schematic by Mark Stoker found on this site. To my knowledge dc voltage can not be stepped up by a transformer. I know the 555 timer produces a TTL logic square wave at a certain frequency set by the resistors and capacitors. This is still not an AC signal so how does the transformer step up this voltage. Also what is the purpose of the transistor. One last question what is the typical impedance of the human body. I know the skin has a large resistance. Thanks