How do I-V curve tracers work?

I-V curve tracers are specialist types of test equipment that sweep an electrical load connected to the solar PV module or string and measure both the current and voltage at multiple points during the sweep. The pairs of current and voltage values are then used to plot an I-V curve directly or to calculate and plot a P-V curve.

To overcome the influence of external factors such as temperature and irradiation, I-V curve tracers typically measure and record irradiance and temperature to allow measurements to be converted to STC to enable an accurate comparison to be made with the PV module specification.

Some I-V tracers also incorporate databases of PV module data to enable measured values in the field to be immediately compared with the values declared by the manufacturer as a means of verifying the fitness for purpose and performance of installed systems.