Brownout - A steady state RMS voltage under nominal by relatively constant percentage.
Battery or Pack - Two or more electrochemical cells electrically interconnected in an appropriate series/parallel arrangement to provide the required operating voltage and current levels. Under common usage, the term "battery" is often also applied to a single cell.
Internal Impedance - The opposition exhibited by a circuit element (cell or battery) to the flow of an alternating current (a.c.) of a particular frequency as a result of resistance, induction and capacitance.
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.
Electrical Line Noise - Radio Frequency Interference (RFI) and Electromagnetic Interference (EMI) are unwanted electrical signals that produce undesirable effects in sensitive electronic equipment.
Spiral Wound - An electrode structure of high surface area created by winding the electrodes and separator into a spiral-wound, jelly-roll configuration.
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).