The graphs on this page are plotted using polarographic conventions where potentials become more negative along the (positive) x-axis and reduction currents are defined as positive.
Equally common is the IUPAC convention where potentials become more positive along the (positive) x-axis and oxidation currents are defined as positive.
For both conventions applying a more negative voltage is a reduction and the observed peak when scanning negative is a reduction current;
applying a more positive voltage is an oxidation and the observed peak when scanning positive is an oxidation current. In practice the difference is a 180° rotation of the graph with a change in sign of the y-axis.

What is the shape of a cyclic voltammogram?

Scanning from +0.2 to -0.5 to +0.2 volts at 100 mV/sec shows a reduction and
then an oxidation peak for a 0.001 M sample with E^{0} = -0.200 volts. The movie shows the scan taking place in real time.