Transcutaneous Electrical Nerves Stimulation

For this reason it is an effective, safe and innocuous therapy for the treatment of all the muscle and skeleton pains, neuralgias, rheumatic pains, articular pains, headaches, lumbar pains, sciatic pains and other affections. T.E.N.S., or Trans cutaneous Electrical Nerves Stimulation, is a particular low frequency wave form that, once applied through electrodes in the area of the cutaneous projection of the pain (triggers area), allows an almost immediate and long lasting reduction of the painful sensibility. 

Circuit blocks of Trans cutaneous Electrical Nerves Stimulation
Typical circuit that is used in the T.E.N.S.
Mechanism through which electrical pulses are able to perform an analgesic effect

Theoretical topics:
The importance of the frequency of the pulses
Gate control theory
T.E.N.S. technology
Theory of releasing the endorphins
Physical principles
Applications for T.E.N.S.