Conventional forward current through the diode is from positive
on the left to negative on the right, indicated by the black
band. The terminal on the left is the anode and the one on
the right is the cathode, often denoted by "a" and "k". In the schematic symbol the
flow of conventional current is shown by the direction of the
arrow, so the top end is the positive anode and the bottom end is
the more negative cathode.