Faradic current

Faradic current
www.physiotherapyphd.com 
During the 1830s, Faraday discovered that bidirectional electrical currents could be induced by a moving magnet. He called this current “Faradic current.” Faradic current can be used to produce muscle contractions.
Faradic type current is short duration interrupted direct current with pulse duration of 0.1–1 ms and frequencies between 50–100 Hz, used for the stimulation of innervated muscles.
For better results in the treatment, faradic current is always surged to produce a near-normal tetanic-like contraction and relaxation of the muscle. The apparatus should have sufficient control to surge the current so that the intensity of successive impulses increases gradually with surges varying in waveform to provide satisfactory muscle contraction and relaxation. The circuit can be modified to give surges of various durations, frequencies and waveforms. Various forms of surge are available, such as trapezoidal, triangular and saw-tooth impulses, and that most suitable for each patient must be selected.