absorber
In a photovoltaic device, the material that readily absorbs photons to generate charge carriers (free electrons or holes).
acceptor
A dopant (impurity) material, such as boron, which has fewer outer shell electrons than required in an otherwise balanced crystal structure, providing a hole, which can accept a free electron and is considered to be an important attribute of photovoltaic materials.
activated shelf life
The length of time, at a specified temperature, that a charged battery can be stored before its capacity falls to an unusable level.
activation voltage(s)
The voltage(s) at which a charge controller will take action to protect the batteries.
adjustable set point
A feature allowing the user to adjust the voltage levels at which a charge controller will become active.
air mass or air mass ratio
Equal to the cosine of the zenith angle or that angle from directly overhead to a line intersecting the sun.
The air mass is an indication of the length of the path solar radiation travels through the atmosphere. An air mass of 1.0 means the sun is directly overhead and the radiation travels through one atmosphere (thickness).
alternating current, AC
A type of electrical current, the direction of which is reversed at regular intervals or cycles.
In the United States, the standard is 120 reversals or 60 cycles per second. Electricity transmission networks use alternating current because voltage can be controlled with relative ease.
Alternating current is easier to transmit over long distances than direct current (DC), and it is the form of electricity used today in most homes and businesses.
ambient temperature
The temperature of a surrounding or an environmental area.
amorphous semiconductor
A non-crystalline semiconductor material that has no long-range order.
amorphous silicon
1. A thin-film, silicon photovoltaic cell having no crystalline structure.
Manufactured by depositing layers of doped silicon on a substrate.
2. An alloy of silica and hydrogen with a disordered, noncrystalline internal atomic arrangement.
It can be deposited in thin-film layers by a number of deposition methods to produce photovoltaic cells on glass, metal, or plastic substrates.
amperage interrupt capability, AIC
Direct current fuses should be rated with a sufficient AIC, amperage interrupt capability, to interrupt the highest possible current.
ampere hour meter
An instrument that monitors current with time.
The indication is the product of current (in amperes) and time (in hours).
ampere, A, amp
1. The basic unit of electric current in the meter-kilogram-second system; equivalent to one coulomb per second.
2. A unit of electrical current or rate of flow of electrons.
One volt across one ohm of resistance causes a current flow of one ampere.
ampere-hour, ampere hour; Ah, AH
A measure of the flow of current (in amperes) over one hour when the rate of flow is one ampere; equal to 3600 coulombs (standard international unit of electric charge).
Used to measure battery capacity.
angle of incidence
The angle that a ray of sun makes with a line perpendicular to the surface.
A surface that directly faces the sun has a solar angle of incidence of zero, but if the surface is parallel to the sun (for example, sunrise striking a horizontal rooftop), the angle of incidence is 90°.
—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.
