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A Colortran ERS. An Ellipsoidal Reflector from a Leko Source Four ERS. Ellipsoidal reflector spot (abbreviated to ERS, or colloquially ellipsoidal or ellipse) is the name for a type of stage lighting instrument, named for the ellipsoidal reflector used to collect and direct the light through a barrel that contains a lens or lens train.
An ellipse (red) obtained as the intersection of a cone with an inclined plane. Ellipse: notations Ellipses: examples with increasing eccentricity. In mathematics, an ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant.
The index ellipsoid is not to be confused with the index surface, whose radius vector (from the origin) in any direction is indeed the refractive index for propagation in that direction; for a birefringent medium, the index surface is the two-sheeted surface whose two radius vectors in any direction have lengths equal to the major and minor semiaxes of the diametral section of the index ...
Available in numerous spot and flood beam spreads. Like all light bulbs, the number represents the diameter of the bulb in 1 ⁄ 8 of an inch. Therefore, a PAR 16 is 51 mm (2 in) in diameter, a PAR 20 is 64 mm (2.5 in) in diameter, PAR 30 is 95 mm (3.75 in) and a PAR 38 is 121 mm (4.75 in) in diameter. A package of four 60-watt light bulbs
English: A diagram showing some basic properties of an ellipse, including The distance to a focus, F , from the centre C , is the eccentricity, e multiplied by the semimajor axis, a . The distance from one focus to the other via any point on the ellipse, P , is always 2 a .
When increases from zero, i.e., assumes positive values, the line evolves into an ellipse that is being traced out in the counterclockwise direction (looking in the direction of the propagating wave); this then corresponds to left-handed elliptical polarization; the semi-major axis is now oriented at an angle .
An electric light, lamp, or light bulb is an electrical component that produces light.It is the most common form of artificial lighting.Lamps usually have a base made of ceramic, metal, glass, or plastic which secures the lamp in the socket of a light fixture, which is often called a "lamp" as well.
The energy consumption can be 70% less than that of a standard incandescent light bulb. Claimed lifetime can be as long as 10,000 hours which is more than ten times that of a standard incandescent light bulb. [7] Unlike fluorescent lamps, which produce light through the electrical excitation of mercury vapor, ESL lamps do not use mercury. [8]