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IEC 60417-5007, [6] the power-on symbol (line), appearing on a button or one end of a toggle switch indicates that the control places the equipment into a fully powered state. (1 or | means on.) IEC 60417-5008, [7] the power-off symbol (circle) on a button or toggle, indicates that using the control will disconnect power to the device. (0 or ...
A rotary hand control turns a shaft that is connected within the infinite switch to a cam and follower. At the off position both power line connections are interrupted. At all on positions the manual contacts connect one of the line terminals to the pilot lamp terminal and one of the terminals for the heating element being controlled.
However, the phrase "toggle switch" is applied to a switch with a short handle and a positive snap-action, whether it actually contains a toggle mechanism or not. Similarly, a switch where a definitive click is heard, is called a "positive on-off switch". [11] A very common use of this type of switch is to switch lights or other electrical ...
A Single-Pole, Single-Throw (SPST) mercury switch on millimetre graph paper, device length approximately 1.5 cm Another mercury switch design. A mercury switch is an electrical switch that opens and closes a circuit when a small amount of the liquid metal mercury connects metal electrodes to close the circuit.
A thermostat exerts control by switching heating or cooling devices on or off, or by regulating the flow of a heat transfer fluid as needed, to maintain the correct temperature. A thermostat can often be the main control unit for a heating or cooling system, in applications ranging from ambient air control to automotive coolant control.
After the control of air flow and temperature was standardized, the use of electromechanical relays in ladder logic to switch dampers became standardized. Eventually, the relays became electronic switches, as transistors eventually could handle greater current loads. By 1985, pneumatic controls could no longer compete with this new technology ...
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If the thermostat is calling for heat, the boiler will fire until the high limit is reached, then shut off (even if the thermostat is still calling for heat). The boiler will re-fire if the boiler water temperature drops below a range around the high limit.