A ceramic capacitor with the designation of CAP CER 3.9PF 3.6KV C0G/NP0 2225 has a capacitance value of 3.9 pF ±0.1pF and a maximum working voltage rating of 3600V (equivalent to 3.6kV). This capacitor falls under the category of C0G, also known as NP0, which is a specific type of ceramic dielectric material used in capacitors for its stable capacitance characteristics across various temperatures. The metric designation 2225 refers to the physical dimensions and shape of this component.