Infinite switch
Encyclopedia
An infinite switch is a type of switch
Switch
In electronics, a switch is an electrical component that can break an electrical circuit, interrupting the current or diverting it from one conductor to another....

 that allows variable power output and is so called because its average output is infinitely variable rather than being limited to a few switched levels. They utilize a bi-metallic strip
Bi-metallic strip
A bimetallic strip is used to convert a temperature change into mechanical displacement. The strip consists of two strips of different metals which expand at different rates as they are heated, usually steel and copper, or in some cases brass instead of copper. The strips are joined together...

 conductive connection across terminals that disconnects with increased temperature. As current passes through the bimetal connection, it will heat and deform, breaking the connection and turning off the power. After a short time, the bimetal will cool and reconnect. Therefore, infinite switches vary the average power delivered to a device by oscillating quickly between on and off states. They may be used for situations that are not sensitive to such changes, such as the resistive heating
Joule heating
Joule heating, also known as ohmic heating and resistive heating, is the process by which the passage of an electric current through a conductor releases heat. It was first studied by James Prescott Joule in 1841. Joule immersed a length of wire in a fixed mass of water and measured the temperature...

 elements in electric stove
Electric stove
An electric stove converts electricity into heat to cook and bake.- History :On September 20, 1859, George B. Simpson was awarded US patent #25532 for an 'electro-heater' surface heated by an platinum-wire coil powered by batteries; in his words, useful to "warm rooms, boil water, cook...

s and kiln
Kiln
A kiln is a thermally insulated chamber, or oven, in which a controlled temperature regime is produced. Uses include the hardening, burning or drying of materials...

s.

Disadvantages the high-speed mechanical switching are erosion of the switch contacts by arcing and generation of radio-frequency interference, and their unsuitability for handling high powers and inductive loads.

See also

  • Bimetal thermostat
  • Pulse-width modulation
    Pulse-width modulation
    Pulse-width modulation , or pulse-duration modulation , is a commonly used technique for controlling power to inertial electrical devices, made practical by modern electronic power switches....

  • Relaxation oscillator
    Relaxation oscillator
    A relaxation oscillator is an oscillator based upon the behavior of a physical system's return to equilibrium after being disturbed. That is, a dynamical system within the oscillator continuously dissipates its internal energy...

  • Dimmer
    Dimmer
    Dimmers are devices used to vary the brightness of a light. By decreasing or increasing the RMS voltage and, hence, the mean power to the lamp, it is possible to vary the intensity of the light output...

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