Static bypass switch - Power-electronics device that can be used to switch from one source to another without interruption in the supply of power. In a UPS, transfer is from Mains 1 to Mains 2 and back. Transfer without interruption is possible due to the fact that there are no mechanical parts and the ultra-fast switching capabilities of the electronic components.
Electrolyte - The medium which provides the ion transport mechanism between the positive and negative electrodes of a cell.
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.
Nominal Voltage - The characteristic operating voltage or rated voltage of a battery.
Load (linear) - Load for which voltage form and current form are similar. Voltage and current are related by Ohm's law U(t) = Z x I(t).
Trickle Charge - A charge at a low rate, balancing losses through local action and/or periodic discharge, to maintain a cell or battery in a fully charged condition.
Frequency - The repetition of cycles measured in Hz. 60 Hz is the standard frequency in the U.S. 50 Hz is the standard frequency in other parts of the world. 60 Hz = 60 cycles per second.