Standard Test Conditions (STC) refer to a set of specific parameters used to evaluate the performance of solar panels and other photovoltaic devices. These conditions typically include a temperature of 25°C, an irradiance of 1000 watts per square meter, and a spectrum of light similar to that of the sun at noon on a clear day. STC provides a consistent basis for comparing the efficiency and output of different solar technologies. By using STC, manufacturers and researchers can ensure that test results are reliable and comparable. This standardization helps consumers make informed decisions when selecting solar products, as it allows for a fair assessment of their performance under controlled conditions.