Power source (safety) - Power source for loads defined as critical by applicable safety regulations. This supply must not be affected by a mains failure and is generally separate from other supplies.
Positive Temperature Coefficient (PTC) - A thermally reactive device which becomes highly resistive at a specific temperature or current.
Current Collector - An inert structure of high electrical conductivity used to conduct current from or to an electrode during discharge or charge.
Thevenin generator - For a given load, it is possible to consider the power supply as a voltage generator, referred to as a Thevenin generator, made up of a perfect voltage Uo generator, in series with an internal impedance Zs - n Uo is the voltage measured across the load terminals, given that the load is to be disconnected (load terminals forming an open circuit), n Zs is the equivalent impedance as seen from the load terminals (again considered an open circuit), obtained by short-circuiting the upstream voltage generator(s).
Load (non-linear) - Load (generally with a switched-mode power supply) generating major harmonic currents. Current wave form is different from voltage wave form. Ohm's law is not applicable. It can be used only with each harmonic.
Series - The interconnection of cells in such a manner that the positive terminal of the first is connected to the negative terminal of the second, and so on, resulting in increased voltage.
Brownout - A steady state RMS voltage under nominal by relatively constant percentage.