Air Mass (Abbrev. AM, "Luftmasse" in German )
When the sun is in a vertical position, the sunlight takes the shortest path through the earth's atmosphere. However, when the sun is positioned at a flat angle, the distance increases by the air mass (AM) factor. This causes a lower radiation intensity and a modified spectral (colour) composition of the sunlight. Outside the atmosphere, AM 0 applies, at a vertical position of the sun AM 1 (= simple atmospheric thickness). For Europe, the annual mean of AM 1.5 is used.
Amorphous silicon (a-Si)
Amorphous silicon is used as the active material in thin-layered solar cells. Unlike monocrystalline or polycrystalline silicon, the atoms atoms are not arranged in a regular crystalline lattice, but irregular without structure. Amorphous silicon cells are vapour-deposited on glass or on a metal film as a substrate material in multiple layers.
Ampere (unit A)
Unit of measurement of electrical current.
Anti-reflection layer
Light that is reflected from a solar cell, can not contribute to power generation. In order to minimize reflection losses, an anti-reflection layer is applied to the solar cells on the front side. This thin layer gives the cells its blue colour. Other colours are possible, but then the anti-reflective effect and thus the efficiency of the cells worsen.
Azimuth
The azimuth is the angle of deviation of the generator surface facing south. In solar technology, the azimuth angle is fixed at 0° for the south. The angular deviation to the west is positive, negative to the east.
Associations
VDE Association for Electrical, Electronic & Information Technologies
VBN Rules of the supply grid operator
TAB Technical connection conditions
VDS Association of Property Insurers
BGV Professional Association Prescriptions and Rules
DGS German Society for Solar Energy
Angle of inclination
The angle of inclination describes the angle between the solar module and the horizontal. The optimal angle of inclination for photovoltaic systems depends on latitude
Alternating current (AC, German Wechselstrom)
Electric current that continually changes its direction. Typical house current changes its direction 100 times per second (50 Hz) and has a nominal voltage of 230 V. The voltage runs sinusoidally. The normal three-phase system consists of 3x 230 leading external conductors. While a house connection is usually single-phase, i.e. with a current-carrying conductor, large customers are supplied with three-phase current to reduce conduction losses.
