This lecture covers the concept of capacitors, which are devices composed of two conductors separated by a non-conductive material. The instructor explains how the capacitance is related to the charge difference between the conductors under a given voltage. The integral form of capacitors is discussed, along with examples of voltage variation across capacitors when subjected to current pulses. The lecture also delves into the analysis of circuits containing resistors and capacitors, emphasizing the mesh law and capacitor current.