Automatic polarity changing device

DETAILED DESCRIPTION An object of the present invention is to eliminate the above mentioned disadvantages of the conventional cataphoresis process.
Another object of the present invention is to provide a polarity changing device for a supply source for use in a cataphoresis apparatus in which change of the above current polarity every cycle of the current flowing through a buffer solution can automatically be performed even if the supply source of the cataphoresis apparatus is cut off on the way to cataphoresis process and the erroneous action may be prevented resulting in an elevation in reliability of measurement.
According to the present invention a device for automatically changing the polarity of a direct current supply source for use in a cataphoresis apparatus comprises a switch for changing the polarity of migration current, a device for generating a functional signal in response to a detection of the finish or the beginning of the migration current, a signal processing device connected to the functional signal generator for processing the functional signal to drive the polarity change switch and a polarity changing device connected between the signal processing device and the polarity change switch for instructing polarity change of the migration current to the polarity change switch and for memorizing the changed polarity of the migration current in spite of switching on or off of a power supply source, the polarity changing device changing the polarity of the migration current to a polarity opposite to the just previous polarity every detection of the finishing or the beginning of the migration current.