Determination of the current-voltage characteristic curve of photovoltaic individual modules as well as of a module string up to a maximum of 1500 V and 15 A. With a simple press of a button, the current power (MPP), peak power, short-circuit current, and open-circuit voltage are displayed on the graphic display within seconds and automatically converted to standard test conditions (STC). The measured and STC-converted characteristic curves are also displayed and compared with the manufacturer-specified curves. This allows for immediate conclusions regarding the current quality status of the PV modules. The measurement data and characteristic curves can be saved after measurement with three reference numbers (system, string, module number) and an additional text comment in the I-V500w, and transferred to a PC or iPad/Tablet via the optically isolated interface or WLAN for further processing (report). A database with the specifications of the most common PV modules can be expanded or updated at any time by the user directly or via the PC interface with the TOPVIEW software. The following measurement values are displayed directly on the I-V500w screen: peak power (at STC) and the currently measured power (MPP), short-circuit current Isc and open-circuit voltage Uoc, as well as Impp and Umpp, fill factor FF in %, a graphical representation of the I-U and PWR characteristic curves at OPC and STC, and the overall test result OK / NOK.