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  2. Dimmer - Wikipedia

    en.wikipedia.org/wiki/Dimmer

    A dimmer is a device connected to a light fixture and used to lower the brightness of the light. By changing the voltage waveform applied to the lamp, it is possible to lower the intensity of the light output.

  3. Pulse-width modulation - Wikipedia

    en.wikipedia.org/wiki/Pulse-width_modulation

    Adjusting the brightness of light emitted by a light source is then merely a matter of setting at what voltage (or phase) in the AC half-cycle the dimmer begins to provide electric current to the light source (e.g. by using an electronic switch such as a triac). In this case the PWM duty cycle is the ratio of the conduction time to the duration ...

  4. Optics - Wikipedia

    en.wikipedia.org/wiki/Optics

    Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. [1]

  5. Electrical ballast - Wikipedia

    en.wikipedia.org/wiki/Electrical_ballast

    A dimmable ballast is very similar to a rapid start ballast, except that the autotransformer is connected to a dimmer. A quadrac type light dimmer can be used with a dimming ballast, which maintains the heating current while allowing lamp current to be controlled. A resistor of about 10 kΩ is required to be connected in parallel with the ...

  6. Magnitude (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Magnitude_(astronomy)

    An illustration of light sources from magnitude 1 to 3.5, in 0.5 increments In astronomy , magnitude is a measure of the brightness of an object , usually in a defined passband . An imprecise but systematic determination of the magnitude of objects was introduced in ancient times by Hipparchus .

  7. Limb darkening - Wikipedia

    en.wikipedia.org/wiki/Limb_darkening

    The light seen is approximately the integral of all emission along the line of sight modulated by the optical depth to the viewer (i.e. 1/e times the emission at 1 optical depth, 1/e 2 times the emission at 2 optical depths, etc.). Near the center of the star, optical depth is effectively infinite, causing approximately constant brightness.

  8. Looking for American-made clothing? Check out these 35 USA ...

    www.aol.com/lifestyle/american-made-clothing...

    When it comes to American-made boots, you can’t go wrong with Red Wing Heritage. True to its name, the brand crafts its footwear in Red Wing, Minnesota, and all of its leather comes from the ...

  9. Zeeman effect - Wikipedia

    en.wikipedia.org/wiki/Zeeman_effect

    The sodium vapour lamp emits light at 589nm, which has precisely the energy to excite an electron of a sodium atom. If it was an atom of another element, like chlorine, shadow will not be formed. [ 18 ] [ failed verification ] When a magnetic field is applied, due to the Zeeman effect the spectral line of sodium gets split into several components.