Myoelectric signals are detected by placing three electrodes on the skin. Two electrodes are positioned so there is a voltage between them when a myoelectric signal occurs. The third electrode is placed in a neutral area, and its output is used to cancel the noise that can otherwise interfere with the signals from the other two electrodes. The output voltage is processed using a device called a differential amplifier. The output of this amplifier has much higher voltage than the myoelectric signals themselves. This higher voltage, which produces significant current, can be used to control electromechanical or electronic devices.