Christmas lights with 8 Functioncontroller

This shows parallel beams from two helium-neon lasers converging to the principal focal point of a 30 cm double convex lens. The rays then enter a diverging lens of focal length -10cm on the right. The laser beams were made visible with a spray can of artificial smoke.

The most important characteristic of a lens is its principal focal length, or its inverse which is called the lens strength or lens "power". Optometrists usually prescribe corrective lenses in terms of the lens power in diopters. The lens power is the inverse of the focal length in meters: the physical unit for lens power is 1/meter which is called diopter.

4 Channel8 Function chaseControllerwith Push Button

The principal focal length of a lens is determined by the index of refraction of the glass, the radii of curvature of the surfaces, and the medium in which the lens resides. It can be calculated from the lens-maker's formula for thin lenses.

For a thin double convex lens, refraction acts to focus all parallel rays to a point referred to as the principal focal point. The distance from the lens to that point is the principal focal length f of the lens. For a double concave lens where the rays are diverged, the principal focal length is the distance at which the back-projected rays would come together and it is given a negative sign. The lens strength in diopters is defined as the inverse of the focal length in meters. For a thick lens made from spherical surfaces, the focal distance will differ for different rays, and this change is called spherical aberration. The focal length for different wavelengths will also differ slightly, and this is called chromatic aberration.

SlideFeatures• 4-Channel Controller • Key Fob • Switching & Dimming with smooth on/off • 350m range • Expandable DescriptionSave money with this 4-channel starter kit. All you need to start your wireless lighting system, comprising of a 4-Zone Key Fob and a 4-Channel Lighting Controller. • 4 channels rated 500W each • Smooth on/off option on all channels • 350m range You can add extra controllers or modules as your system expands. For more details about each item, please see individual product pages. Item No. LS4SKIT Product Video

Save money with this 4-channel starter kit. All you need to start your wireless lighting system, comprising of a 4-Zone Key Fob and a 4-Channel Lighting Controller. • 4 channels rated 500W each • Smooth on/off option on all channels • 350m range You can add extra controllers or modules as your system expands.