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Two light switches in one box. The switch on the right is a dimmer switch. The switch box is covered by a decorative plate. The first light switch employing "quick-break technology" was invented by John Henry Holmes in 1884 in the Shieldfield district of Newcastle upon Tyne. [1]
In building wiring, multiway switching is the interconnection of two or more electrical switches to control an electrical load from more than one location.A common application is in lighting, where it allows the control of lamps from multiple locations, for example in a hallway, stairwell, or large room.
Leviton was founded in 1906 by Russian immigrants Evser Leviton and his son Isidor Leviton when they began manufacturing brass mantle tips for natural gas lights in Manhattan's Lower East Side. [ 2 ] [ 3 ] [ 4 ] In 1910, Isidor designed a screw-in lampholder for the newly invented electric light bulb and within ten years the lampholders were ...
Wire crossover symbols for circuit diagrams. The CAD symbol for insulated crossing wires is the same as the older, non-CAD symbol for non-insulated crossing wires. To avoid confusion, the wire "jump" (semi-circle) symbol for insulated wires in non-CAD schematics is recommended (as opposed to using the CAD-style symbol for no connection), so as to avoid confusion with the original, older style ...
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. There are several different basic ...
Hamilton was a founder of the field of occupational safety and health and published the first edition of her manual, Industrial Toxicology, in 1934, yet in print in revised forms. [291] An important step in the understanding of childhood lead poisoning occurred when toxicity in children from lead paint was recognized in Australia in 1897. [ 121 ]
Most accordions have automatic or preset switches, similar to voice selection on an electronic keyboard, or (more precisely) to a preset combination action in a pipe organ. These switches control which reed ranks are enabled (opened up) or disabled (closed off): some switches enable a single reed rank, others enable several simultaneous reed ranks.