The 91150-KG5 Reference Cell and Meter is an integral part of solar simulator calibration and solar cell I-V characterization. It consists of a readout device and a 2 x 2 cm calibrated solar cell made of monocrystalline silicon with KG5 window. The cell is also equipped with a thermocouple assembled in accordance with IEC 60904-2. The certification is accredited by NIST to the ISO-17025 standard and is traceable both to the National Renewable Energy Laboratory (NREL), and to the International System of Units (SI). It reads solar simulator irradiance in sun units; one sun is equal to 1000 W/m2 at 25 °C and Airmass 1.5 Global Reference. This tool's primary use is the testing of photovoltaic cells under standard conditions. The Readout Meter includes two BNC connectors for analog outputs for the sun irradiance and the temperature.