A surface NMES stimulation device the device has a control processor, a voltage regulator connected to a high voltage supply, a bridge of control switches, and electrodes or electrode terminals connected in the bridge to receive drive signals via the control switches. The processor directs a drive scheme for the bridge control switches in which charge build-up on a user's skin is allowed to dissipate to ground in an inter-pulse interval. An isolation capacitor isolates the high voltage supply from the electrodes, and charging of the capacitor only occurs if a switch allows it. Sensors senses supply voltage and bridge current and the processor monitors there to determine further stimulation and faults.