A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition is sometimes remembered using the mnemonic CCD for cathode current departs. A conventional current describes the direction in which positive electronic charges move. For example, reversing the current direction in a Daniell galvanic cell would produce an electrolytic cell, where the copper electrode is the positive terminal and the anode. 2  In a diode, the cathode is the negative terminal at the pointed end of the arrow symbol, where current flows out of the device.