When we were just trying out the stun gun with short bursts to the arm and even the stomach, the pain was practically nothing. But when that thing digs into you and discharges 300,000 volts into your guts for a second or two, the pain is quite a bit greater. I can easily see how a mugger would have to be either stupid or insane to attack someone if they knew the victim had one of these things. This is the fun part. This is caused by the dielectric breakdown of the air between the electrodes.
Air breaks down at three million volts per meter.
This happens dozens of times per second. Instead, the electricity flows directly into the person, whose body has a much higher dielectric constant than the air. Unfortunately I was unable to obtain a schematic ciruitry plan for my particular gun, so I had to go with a schematic and description of a different gun altogether. Basically, the circuitry consists of a multi-stage system that serves mainly to increase the voltage from each previous stage. The first stage has transistors which serve to convert the direct current from the batteries to an alternating current.