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  2. Thermal management of high-power LEDs - Wikipedia

    en.wikipedia.org/wiki/Thermal_management_of_high...

    Most of the electricity in an LED becomes heat rather than light – about 70% heat and 30% light. [1] If this heat is not removed, the LEDs run at high temperatures, which not only lowers their efficiency, but also makes the LED less reliable, shortens its lifespan. Thus, thermal management of high power LEDs is a crucial area of the research ...

  3. Joule heating - Wikipedia

    en.wikipedia.org/wiki/Joule_heating

    Joule heating (also known as resistive, resistance, or Ohmic heating) is the process by which the passage of an electric current through a conductor produces heat.. Joule's first law (also just Joule's law), also known in countries of the former USSR as the Joule–Lenz law, [1] states that the power of heating generated by an electrical conductor equals the product of its resistance and the ...

  4. Thyratron - Wikipedia

    en.wikipedia.org/wiki/Thyratron

    Rare Z806W relay tube used in elevators. Low-power thyratrons (relay tubes and trigger tubes) were manufactured for controlling incandescent lamps, electromechanical relays or solenoids, for bidirectional counters, to perform various functions in Dekatron calculators, for voltage threshold detectors in RC timers, etc. Glow thyratrons were optimized for high gas-discharge light output or even ...

  5. Thermal expansion valve - Wikipedia

    en.wikipedia.org/wiki/Thermal_expansion_valve

    A thermal expansion valve or thermostatic expansion valve (often abbreviated as TEV, TXV, or TX valve) is a component in vapor-compression refrigeration and air conditioning systems that controls the amount of refrigerant released into the evaporator and is intended to regulate the superheat of the refrigerant that flows out of the evaporator ...

  6. Electric heating - Wikipedia

    en.wikipedia.org/wiki/Electric_heating

    The heat pump uses an electric motor to drive a reversed refrigeration cycle, that draws heat energy from an external source such as the ground or outside air (or the interior of a refrigerator) and directs that heat into the space to be warmed (in case of a fridge, the kitchen). This makes much better use of electric energy than direct ...

  7. Vacuum tube - Wikipedia

    en.wikipedia.org/wiki/Vacuum_tube

    Later thermionic vacuum tubes, mostly miniature style, some with top cap connections for higher voltages. A vacuum tube, electron tube, [1] [2] [3] valve (British usage), or tube (North America) [4] is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied.

  8. AOL Mail

    mail.aol.com

    Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!

  9. Light valve - Wikipedia

    en.wikipedia.org/wiki/Light_valve

    The light valve thus consists of the two polarising filters, where one has a voltage controlled switch function thanks to the properties of the liquid crystals. This type of valve is often referred to as a liquid crystal light valve. The other principle, the reflective LV, works by either reflecting the light towards the target or deflecting it ...