provides sufficient time for generation of a stimulation pulse thereafter electrodes 11 and 12 are temporarily shorted out so as to become discharged during the above mentioned 5 millisecond sensing period a c signals which bypass transistor 44 are applied to an rms converter circuit comprising amplifier 31 diodes 185 and 186 resistors 153 through 157 and capacitor 212 amplifier 31 and diode 185 cooperate to function as a precision diode which rectifies the a c signal the rectified signal charges capacitor 212 during the 5 millisecond emg sensing period thereafter during the stimulation period and the pause period capacitor 212 discharges through resistor 157 resistor 157 is adjustable for controlling the discharge time for capacitor 212 while resistor 156 is adjustable for controlling the charging time of capacitor 212 the charge on capacitor 212 provides a voltage which is amplified by amplifiers 32 and 33 for application to control line 21 variable resistor 160 provides for adjustment of the gain produced by the combination of amplifiers 32 and 33 as stated previously signals on control line 21 are applied to stimulator 17 thus capacitor 212 acts as a memory device for storing control signal samples so as to prevent loss of the control signal while transistor switch 44 is closed the details of stimulator 17 are shown in fig5 the output of this circuit is a series of pulses on lines 18 19 having a current which is proportional to the voltage appearing on control line 21 the pulses persist for.