Abstract: The disclosure teaches an electronic apparatus for stimulating the muscles of a patient by disposing electrodes on the outer surface of the patient in the vicinity of the muscles. The stimulating wave consists of a composite signal comprising bursts of a sine wave, having a frequency greater than 500 Hz, and preferably in the range of 2000-3000 Hz, modulated by a signal at a frequency less than 500 Hz, and preferably in the range of 40-60 Hz. The bursts are applied for 2-20 second periods separated by 2-50 second rest intervals. The apparatus includes safety circuits which sense the current to the electrodes and turn off the stimulating waves on detection of a no load or overload condition. The apparatus also includes a power amplifier with a gain control and a switch associated with the gain control such that, if, at the beginning of any treatment, the gain control is not set to zero, stimulating waves will not be applied.

Abstract: A protective device to interrupt the flow of current at a work place when current of a magnitude to endanger life flows through the body of a person whereby at least two electrodes with skin contact are applied on a person which electrodes are connected to a voltage sensor which determines the voltage difference between the electrodes when current flows through the body and is designed to release a signal to a circuit breaking device which interrupts the flow of current when the current passing through the body exceeds the admissible value.

Abstract: A medical instrument, specifically shown as a dialysis machine, incorporates an electrically isolated and hermetically sealed high thermal flux heater in conjunction with means for vectorially cancelling alternating current signal components generated in the operation of the machine. Because of electrical coupling between the medical instrument and a human patient blood stream, large ground leakage currents can result in electrical shock for a patient if the ground wire of the machine becomes open circuited. However, the combination of a specially modified dialysate fluid heater with an extremely large and dependable isolation resistance and operating mode dependent vectorial compensation for resistive and capacitive leakage current permits total leakage current from chassis to ground to be brought below a hitherto unattainable 1 microamp level.