A diode connected in parallel with a PV module to provide an alternate current path in case of module shading or failure. G,H I,J K,L N,O P,Q U,V W,X Y,Z This Page Page 2 Page 3 Capacitance (C): The storage of energy in an electrostatic field, which creates an opposition to a change in voltage. A capacitor has two metal plates, separated by an air space or other insulating material, across which an electrical charge can build up but not flow. Capacitance in a circuit creates a phase difference between the voltage and the current in that circuit, in which the voltage lags or peaks after the amperage. The unit of capacitance is the farad (F).