Abstract: Electrobiological stimulation is carried out transcranially by applying high frequency squarewave bursts exhibiting no d.c. term across the cranial region. Such stimulation is commenced employing ramp generators and positive and negative voltage converters which evolve the requisite baseform and burst frequencies having a voltage waveform which is square in nature. Both voltage and current are sensed and subjected to comparator logic in conjunction with predetermined thresholds and windows. Overcurrent detection and overvoltage detection is provided in hard wired fashion to assure rapid shutdown response. D.C offset detection is provided along with waveform balance tests to further assure the safety of the system. Diagnostic procedures as well as therapeutic procedures may be carried out with a system version which provides for the application of a stimulus in conjunction with safety monitoring and controller based development of stimulating waveforms, all of which exhibits no d.c. term.