Patent No. 4503863 Method and apparatus for transcutaneous electrical stimulation
Patent No. 4503863 Method and apparatus for transcutaneous electrical stimulation (Katims, Mar 12, 1985) Abstract A method and apparatus for monitoring and obtaining actual bio-electrical characteristics of a subject under predetermined conditions of evoked response stimuli, and by interaction with a computer, applying cutaneous electrical stimulation to the subject, using a signal generator to modify current amplitude and frequency in a direction to achieve bio-electrical characteristics in the subject related to the actual bio-electrical characteristics monitored. The signal generator uses a sinusoidal waveform output, with battery power passed through a transformer to power a transconductance amplifier to obtain constant current output despite resistance changes in the line with the subject, and with the transformer not placed in the signal path of the sinusoidal waveform. The signal may be obtained from a sinusoidal oscillato