- electrical pain threshold: The Digitimer High Voltage Stimulator model DS74 provides high voltage pulses of constant current up to 100mA, pulses are of short duration and the output current is variable ranging between 0 and 100mA. The Digitimer is used to evaluate the pain perception threshold by applying electrical stimulation to the index finger to a pulse duration of 200 ls. The initial current applied is 0mA and increases of 0.1 mA until the subject feels pain.