Electrotherapy device

An apparatus for applying electrical current to biological tissue such as skin, bone or muscle. A portable housing can be powered with a battery or attached cord leading to an alternating current or direct current power supply. An extendible arm permits a person to apply the treatment without assistance, and the housing can be operated with a single hand. An amplifier generates a high voltage direct current, and a controller generates a high quality square waveform output. Such waveform comprises an output to an electrode assembly in electrical contact with the biological tissue. The electrode assembly comprises at least one negative electrode and at least one positive electrode which generate an electric current through the biological tissue between the positive and negative electrodes. The electrode assembly is movable relative to the biological tissue so that the current path is continually changing. The electrode assembly can comprise a plurality of negative and positive electrodes to create multiple current paths through the biological tissue. The controller can selectively modify output signal functions such as the amplitude, pulse rate, pulse sweep, frequency, and frequency sweep rate to provide different electrical currents to the biological tissue during operation. A display engaged with the controller indicates the output signal functions and provides controls for selectively modifying the output signal function.