from Danger Room by David Hambling
Existing Tasers use an electric pulse that lasts a few microseconds, and delivers around .07 Joules of energy. This is sufficiently intense to disrupt nerve cell membranes, effectively paralyzing the neuromuscular system however tough you are. The microsecond pulses are repeated over a five-second cycle.
This meets police requirements, allowing a suspect to be incapacitated for long enough to make a quick arrest. The U.S. military is looking at a longer keeping people stunned for much longer, however. The Joint Nonlethal Weapons Directorate is looking at a new generation of electroshock weapon that might knock the target down for fifteen minutes with a single ultra-short pulse.