Cubicle (single UPS unit) - Cubicle containing a rectifier/charger, an inverter and a bypass. Connected to a battery, it operates alone, forming a single UPS. Compare with Cubicle (parallel UPS unit).
Micro-outage (or micro-interruption) - Total loss in the supply of power for 10 ms.
Specific Energy - The ratio of the energy output of a cell or battery to its weight (Wh/kg). This term is used interchangeably with gravimetric energy density.
Polarization - The lowering of the potential of a cell or electrode from its equilibrium value caused by the passage of an electric current.
Inverter (on-line) - UPS configuration in which the inverter is in series mounted between the mains and the load. All power drawn by the load passes via the inverter. This is the only configuration used for high outputs.
Internal Resistance (IR) - The opposition exhibited by a circuit element to the flow of direct current (d.c.). In a cell, the internal resistance is the sum of the ionic and electronic resistances of the cell components.
Current Density - The current per unit active area of the surface of an electrode.