scribing
The cutting of a grid pattern of grooves in a semiconductor material, generally for the purpose of making interconnections.
A process in which a semiconductor wafer is etched with deep groves so it can be broken into smaller pieces.
sealed battery
A battery with a captive electrolyte and a resealing vent cap, also called a "valve-regulated battery". An electrolyte cannot be added.
seasonal depth of discharge
An adjustment factor used in some system sizing procedures which "allows" the battery to be gradually discharged over a 30-90 day period of poor solar insolation.
This factor results in a slightly smaller photovoltaic array.
secondary battery, secondary cell
Any battery that can be recharged; that is, one which can receive an additional charge after its primary one.
self-discharge
The rate at which a battery, without a load, will lose its charge.
semiconductor
1. Any material that has a limited capacity for conducting an electric current.
Certain semiconductors, including silicon, gallium arsenide, copper indium diselenide, and cadmium telluride, are uniquely suited to the photovoltaic conversion process.
2. A solid-state crystalline material having values of electrical resistivity intermediate between metals and insulators.
The conductivity of semiconductors can be controlled by adding very small amounts of foreign elements called dopants (chemical impurities added in small quantities to an otherwise pure semiconductor material to modify the electrical properties of the material).
Conductivity is facilitated not only by negatively charged electrons, but also by positively charged holes, and it is sensitive to temperature, illumination, and magnetic field.
series connection
A way of joining photovoltaic cells by connecting positive leads to negative leads; such a configuration increases the voltage.
series controller
A charge controller that interrupts the charging current by open-circuiting the photovoltaic (PV) array.
The control element is in a series with the photovoltaic array and battery.
series regulator
Type of battery charge regulator where the charging current is controlled by a switch connected in a series with the photovoltaic module or array.
series resistance
Parasitic resistance to current flow in a solar cell due to mechanism factors; such as, resistance from the bulk of the semiconductor material, and the resistance of the metallic contacts and interconnections.
shallow-cycle battery
A battery with small plates that cannot withstand many discharges to a low state-of-charge.
shelf life of batteries
The length of time, under specified conditions, that a battery can be stored so that it keeps its guaranteed capacity.
short-circuit current
The electrical current flowing freely through an external circuit that has no load or resistance; the maximum current possible.
shunt controller
A charge controller that redirects or shunts excessive charging current away from a battery.
The controller requires a large heat sink to dissipate the current from the short-circuited photovoltaic array.
Most shunt controllers are for smaller systems producing 30 amperes or less.
shunt load, shunt loading
An electrical load employed to make use of excess generated power when it is not needed for its primary uses; such as, a residential photovoltaic system that employs power for domestic water heating when it is not needed for purposes as operating lights or running heating systems.
—The information for the entries in this unit were compiled primarily from data
provided in the following source:
"U.S. Department of Energy, Energy Efficiency and Renewable Energy"
consisting of definitions of many important terms having to do with electricity,
power generation, concentrating solar power (CSP), solar heating, solar lighting,
and solar electricity, also known as photovoltaic (PV).
Information was also compiled from the
Academic Press Dictionary of Science and Technology; Edited by Christopher Morris;
Academic Press; Harcourt Brace Jovanovich, Publishers; New York; 1992;
as well as,
McGraw-Hill Dictionary of Scientific and Technical Terms, 4th edition;
Sybil P. Parker, editor in chief; McGraw-Hill, Inc.; 1989.
Index of additional Scientific and Technological Topics.
