In electronics and telecommunications, a crossbar switch is a collection of switches arranged in a matrix configuration. A crossbar switch has multiple input and output lines that form a crossed pattern of interconnecting lines between which a connection may be established by closing a switch located at each intersection, the elements of the matrix. Originally, a crossbar switch consisted literally of crossing metal bars that provided the input and output paths. Later implementations achieved the same switching topology in solid-state electronics. The crossbar switch is one of the principal telephone exchange architectures, together with a rotary switch, memory switch, and a crossover switch.
Crossbar telephone exchange of 1903 for four subscribers (vertical bars), having four cross-bar talking circuits (horizontal bars), and one bar to connect the operator (T). The lowest cross-bar connects idle stations to ground to enable the signaling indicators (F). The switch is operated manually with metal pins that create a connection between the horizontally and vertically arranged bars.
Western Electric 100-point six-wire Type B crossbar switch
Late-model Western Electric crossbar switch
Back of Type C
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of switch is an electromechanical device consisting of one or more sets of movable electrical contacts connected to external circuits. When a pair of contacts is touching current can pass between them, while when the contacts are separated no current can flow.
Electrical switches. Top, left to right: circuit breaker, mercury switch, wafer switch, DIP switch, surface mount switch, reed switch. Bottom, left to right: wall switch (U.S. style), miniature toggle switch, in‑line switch, push-button switch, rocker switch, microswitch.
Three push button switches (Tactile Switches). Major scale is inches.
A toggle switch in the "on" position
Triple-pole single-throw (TPST or 3PST) knife switch used to short the windings of a three‑phase wind turbine for braking purposes. Here the switch is shown in the open position.
