Many types of these devices exist. Stun guns, batons (or prods), and belts administer an electric shock by direct contact, whereas Tasers (conducted electrical weapons) fire projectiles that administer the shock through thin flexible wires. Long-range electroshock projectiles, which can be fired from ordinary shotguns and do not need the wires, have also been developed.
Jack Cover, a NASA researcher, began developing the Taser in 1969. By 1974, he had completed the device, which he named after his childhood hero Tom Swift ("Thomas A. Swift's electric rifle"). The Taser Public Defender used gunpowder as its propellant, which led the Bureau of Alcohol, Tobacco and Firearms to classify it as a firearm in 1976. Cover's patent was adapted by Nova Technologies in 1983 for the Nova XR-5000, their first non-projectile hand-held style stun gun. The XR-5000 design was widely copied as the source for the compact handheld stun gun used today.
Electroshock weapon technology uses a temporary high-voltage, low-current electrical discharge to override the body's muscle-triggering mechanisms. Commonly referred to as a stun gun, electroshock weapons are a relative of cattle prods, which have been around for over 100 years and are the precursor of stun guns. The recipient is immobilized via two metal probes connected via wires to the electroshock device. The recipient feels pain, and can be momentarily paralyzed while an electric current is being applied. Essential to the operation of electroshock, stun guns and cattle prods is sufficient current to allow the weapon to stun. Without current these weapons cannot stun and the degree to which the weapon is capable of stunning depends on its proper use of current. It is reported that applying electroshock devices to more sensitive parts of the body is even more painful. The maximum effective areas for stun gun usage are upper shoulder, below the rib cage, and the upper hip. High voltages are used, but because most devices use a non-lethal current, death does not usually occur from a single shock. The resulting "shock" is caused by muscles twitching uncontrollably, appearing as muscle spasms.
The internal circuits of most electroshock weapons are fairly simple, based on either an oscillator, resonant circuit (a power inverter), and step-up transformer or a diode-capacitor voltage multiplier to achieve an alternating high-voltage discharge or a continuous direct-current discharge. It may be powered by one or more batteries depending on manufacturer and model. The amount of current generated depends on what stunning capabilities are desired, but without proper current calculations, the cause and effect of high voltage is muted. Output voltage is claimed to be in the range of 100 V up to 6 kV; current intensity output is claimed to be in the range of 100 to 500 mA; individual impulse duration is claimed to be in the range of 10 to 100 µs (microseconds); frequency of impulse is claimed to be in the range of 2 to 40 Hz; electrical charge delivered is claimed to be in the range of 15 to 500 µC (microcoulombs); energy delivered is claimed to be in the range of 0.9 to 10 J. The output current upon contact with the target will depend on various factors such as target's resistance, skin type, moisture, bodily salinity, clothing, the electroshock weapon's internal circuitry, discharge waveform, and battery conditions.