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.
Alloy - A mixture of several other metals or a metal and a non-metal.
E-Rate - Discharge or charge power, in watts, expressed as a multiple of the rated capacity of a cell or battery which is expressed in watt-hours. For example, the E/10 rate for a cell or battery rated at 17.3 watt-hours is 1.73 watts. (This is similar to the method for calculating C-Rate.)
Gravimetric Energy Density - The ratio of the energy output of a cell or battery to its weight (Wh/kg). This term is used interchangeably with specific energy.
Charger - Device associated with the rectifier and used to supply the battery with the electrical power (DC current) required to recharge and/or float charge the battery, thus ensuring the rated backup time.
RMS Voltage - The range of usable voltage + or - 170 VAC.
Blackout - A zero voltage condition lasting for more than two cycles. Same as a power failure
