6. Transcranial voltage and current thresholds of muscle potentials in upper and lower extremities related to head impedance and electrode montage

Design of transcranial pulse intelligent monitoring stimulator

“…In the experimental procedure, the effective value of current is usually set in the range of 0.5 mA -2 mA, depending on the tolerance of the subject, to ensure that the physiological effects of electrical stimulation are not significantly uncomfortable. The standard resistance at 5 kΩ was selected as a dummy load to simulate cranial impedance, and the electrical pulse signal was applied through the transcranial pulse intelligent monitoring stimulator, and the rectangular pulse current was generated at both ends of the load as shown in Figure 5 to monitor the current output parameters of transcranial electrical stimulation [8] , and the detailed data measured experimentally, are shown in Table 1. The output voltage of the transcranial pulse intelligent monitoring stimulator is affected by different impedances, so the system is designed on the basis of the hardware platform, the software uses a call to the PID function to correct the output, which is essentially changing the on-time of the field effect tube by changing the PWM wave duty cycle, which in turn controls the voltage output and keeps the current flowing through both ends of the load constant [9][10] .…”