Stun guns are weapons designed for lawful self defence or defence of others by temporarily incapacitating a person from a reasonably safe distance or a distance in the reach of hand while reducing the likelihood of serious injuries or death.
The basic idea of a stun gun is to disrupt the body’s communication system. Stun guns generate a high-voltage, low-amperage electrical charge. In simple terms, this means that the charge has a lot of pressure behind it, but not that much intensity. When you press the stun gun against an attacker and hold the trigger, the charge passes into the attacker's body. Since it has a fairly high voltage, the charge will pass through heavy clothing and skin. But at around 3 milliamps, the charge is not intense enough to damage the attacker's body unless it is applied for extended periods of time.
The device can generate 50000V to 150000V from a simple 9V or 12V battery. The device uses a series of transformers, capacitors and diodes together with the principles of physics (P = V*I or power equals current times voltage). The use of stun guns in some countries are banned, yet they are being used by the law and order systems to maintain peace.