Valve Regulated Lead Acid (VRLA) recombination batteries
Accumulators provided with safety unidirectional valves which open with excessive internal pressure. There are two constructive versions: AGM (or starved) and GEL. The formers contain the electrolyte in a micro porous support, while the latters keep it in a gel type support.
A voltage-dependent variable resistor. Normally used to protect sensitive equipment from power spikes or lightning strikes by shunting the energy to ground.
Vertical Multijunction Cell (VMJ)
Composed cell, consisting of different multilayer semiconductor materials, which allows the portions of solar spectrum to be converted in electricity at different depths; this increases the total conversion efficiency of the incident light. Also defined as Split spectrum cell.
Unit of measure of the electromotive force or of the potential difference between two points of an electric array. Across a PV cell the voltage is of about 0.5 V, while across a PV module it's of 17 V (in the point of maximum power).
A measure of the force or "push" given the electrons in an electrical circuit; a measure of electrical potential. One volt produces one amp of current when acting against a resistance of one ohm.