stun gun, hand-held electronic device that produces a high-voltage pulse that can immobilize a person for several minutes with no permanent damage in most cases. It is powered by ordinary batteries, which supply power to a circuit containing transformers, oscillators, capacitors, and electrodes. In some versions the electrodes are connected to the gun by wires and may be shot at a person. The transformers increase the voltage in the circuit to between 20,000 and 150,000 V and reduce the current proportionally. The oscillators fluctuate the current to produce a specific pulse frequency, and the current charges the capacitors. Connecting the electrodes to a person's body releases high-voltage electrical energy at a frequency pattern designed to interfere with the neurological impulses that travel through the human body to control voluntary muscle movement. The use of stun guns has been associated with death in some cases, typically when the person on whom the gun was used on has taken drugs or has a pre-existing heart condition; the use of device multiple times also appears to be a factor. The degree to which the stun gun may have contributed to the deaths is unclear, but studies with pigs have shown that repeated shocks can cause heart stress and a test of some of the devices showed that a few delivered more current than expected.