The CAP CER 3900PF 100V X7R 0805 is a type of ceramic capacitor. It has a capacitance value of 3900 picoFarads and operates at a voltage rating of 100 Volts. The 'X7R' classification indicates that this capacitor has high thermal stability and can handle changes in temperature without significant degradation of its electrical properties. This component is designed with the metric 0805 dimensions, which measures 2.0 mm x 1.6 mm (EIA 0402). It features a capacitance tolerance of ±10% and was introduced as part of the 2012 metric series.