Most household electrical systems use AC current rated at120 volts and 60 cycles per second, where one cycle refers to two complete reverses in direction of the flow. A current of one amp drawn from a battery for 10 hours would consume 10 amp hours of charge from the battery. Fundamentally, a measurement of electrical charge. The filament emits visible light when heated to extreme temperatures by passage of electric current through it. Used in array direct water pumping.
Self discharge represents energy lost to internal chemical reactions within the cell.
Often the resistance of a shunt is known precisely and is used to determine amperage by measuring the voltage across it and using ohms law. A PV manufacturing technique where silicon is vapor deposited, a few molecules thick, onto another material usually steel or plastic.