ELECTROTHERAPY DEVICE

Apparatus for applying electrical current to biological tissue such as skin, bone or muscle. A portable housing (10) can be powered with a battery (24) or attached cord leading to an alternating current or direct current power supply. An amplifier (26) generates a high voltage direct current, and a controller (22) generates a high quality squar e waveform, output to an electrode assembly (12) in electrical contact with the biological tissue. The electrode assembly comprises at leas t one negative electrode (16) and at least one positive electrode (14). The electrode assembly is movable relative to the biological tissue so that the current path is continually changing, and comprises a plurality of negative and positive electrodes to create multiple current paths. The controller can selectively modify output signal functions such as the amplitude, pulse rate, pulse sweep, frequency, and frequency swe ep rate to provide different electrical currents to the biological tissue.