The technology of computer keyboards includes many elements. Among the more important of these is the switch technology that they use. Computer alphanumeric keyboards typically have 80 to 110 durable switches, generally one for each key. The choice of switch technology affects key response and pre-travel. Virtual keyboards on touch screens have no physical switches and provide audio and haptic feedback instead. Some newer keyboard models use hybrids of various technologies to achieve greater cost savings or better ergonomics.
A relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof.
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.
Ladder logic was originally a written method to document the design and construction of relay racks as used in manufacturing and process control. Each device in the relay rack would be represented by a symbol on the ladder diagram with connections between those devices shown. In addition, other items external to the relay rack such as pumps, heaters, and so forth would also be shown on the ladder diagram.
A silicon controlled rectifier or semiconductor controlled rectifier is a four-layer solid-state current-controlling device. The name "silicon controlled rectifier" is General Electric's trade name for a type of thyristor. The principle of four-layer p–n–p–n switching was developed by Moll, Tanenbaum, Goldey, and Holonyak of Bell Laboratories in 1956. The practical demonstration of silicon controlled switching and detailed theoretical behavior of a device in agreement with the experimental results was presented by Dr Ian M. Mackintosh of Bell Laboratories in January 1958. The SCR was developed by a team of power engineers led by Gordon Hall and commercialized by Frank W. "Bill" Gutzwiller in 1957.
A residual-current device (RCD), residual-current circuit breaker (RCCB) or ground fault circuit interrupter (GFCI) is an electrical safety device that quickly breaks an electrical circuit with leakage current to ground. It is to protect equipment and to reduce the risk of serious harm from an ongoing electric shock. Injury may still occur in some cases, for example if a human receives a brief shock before the electrical circuit is isolated, falls after receiving a shock, or if the person touches both conductors at the same time.
Caps Lock⇪ Caps Lock is a button on a computer keyboard that causes all letters of bicameral scripts to be generated in capital letters. It is a toggle key: each press reverses the previous action. Some keyboards also implement a light to give visual feedback about whether it is on or off. Exactly what Caps Lock does depends on the keyboard hardware, the operating system, the device driver, and the keyboard layout. Usually, the effect is limited to letter keys. Letters of non-bicameral scripts and non-letter characters are generated normally.
A kill switch, also known more formally as an emergency brake, emergency stop (E-stop), emergency off (EMO), or emergency power off (EPO), is a safety mechanism used to shut off machinery in an emergency, when it cannot be shut down in the usual manner. Unlike a normal shut-down switch or shut-down procedure, which shuts down all systems in order and turns off the machine without damage, a kill switch is designed and configured to abort the operation as quickly as possible and to be operated simply and quickly. Kill switches are usually designed to be noticeable, even to an untrained operator or a bystander.
In electrical wiring, a light switch is a switch most commonly used to operate electric lights, permanently connected equipment, or electrical outlets. Portable lamps such as table lamps may have a light switch mounted on the socket, base, or in-line with the cord. Manually operated on/off switches may be substituted by dimmer switches that allow controlling the brightness of lamps as well as turning them on or off, time-controlled switches, occupancy-sensing switches, and remotely controlled switches and dimmers. Light switches are also found in flashlights, vehicles, and other devices.
A doorbell is a signaling device typically placed near a door to a building's entrance. When a visitor presses a button, the bell rings inside the building, alerting the occupant to the presence of the visitor. Although the first doorbells were mechanical, activated by pulling a cord connected to a bell, modern doorbells are electric, operated by a pushbutton switch. Modern doorbells often incorporate intercoms and miniature video cameras to increase security.
A fire alarm control panel (FACP), fire alarm control unit (FACU), fire indicator panel (FIP), or simply fire alarm panel is the controlling component of a fire alarm system. The panel receives information from devices designed to detect and report fires, monitors their operational integrity, and provides for automatic control of equipment, and transmission of information necessary to prepare the facility for fire based on a predetermined sequence. The panel may also supply electrical energy to operate any associated initiating device, notification appliance, control, transmitter, or relay. There are four basic types of panels: coded panels, conventional panels, addressable panels, and multiplex systems.
The Option key, ⌥, is a modifier key present on Apple keyboards. It is located between the Control key and the Command key on a typical Mac keyboard. There are two Option keys on modern Mac desktop and notebook keyboards, one on each side of the space bar.
On analog telephone lines with special services, a flash or register-recall signal is used to control functions on the public telephone exchange, PBX or VoIP ATA.
An electronic symbol is a pictogram used to represent various electrical and electronic devices or functions, such as wires, batteries, resistors, and transistors, in a schematic diagram of an electrical or electronic circuit. These symbols are largely standardized internationally today, but may vary from country to country, or engineering discipline, based on traditional conventions.
A wire spring relay is a type of relay, that has springs made from drawn wires of nickel silver, rather than cut from flat sheet metal as in the flat-spring relay. This class of relays provided manufacturing and operating advantages over previous designs. Wire spring relays entered mass production in the early 1950s.
A pneumatic circuit is an interconnected set of components that convert compressed gas into mechanical work. In the normal sense of the term, the circuit must include a compressor or compressor-fed tank.
A magnetic starter is an electromagnetically operated switch which provides a safe method for starting an electric motor with a large load. Magnetic starters also provide under-voltage and overload protection and an automatic cutoff in the event of a power failure.
Registration is the technique of choosing and combining the stops of a pipe organ in order to produce a particular sound. Registration can also refer to a particular combination of stops, which may be recalled through combination action. The registration chosen for a particular piece will be determined by a number of factors, including the composer's indications, the time and place in which the piece was composed, the organ the piece is played upon, and the acoustic environment within which the organ resides.
Automatic test system switching test equipment allows for high-speed testing of a device or devices in a test situation, where strict sequences and combinations of switching must be observed. By automating the process in this way, the possibility of test errors and inaccuracies is minimized, and only systematic errors would generally be encountered due to such as an incorrect programmed test condition. This eliminates error due to human factors and allows application of a standard test sequence repetitively. The design of a test system’s switching configuration is governed by the test specification, which is derived from the functional tests to be performed.
The Atari CX40 joystick was the first widely used cross-platform game controller. The original CX10 was released with the Atari Video Computer System in 1977 and became the primary input device for most games on the platform. The CX10 was replaced after a year by the simpler and less expensive CX40. The addition of the Atari joystick port to other platforms cemented its popularity. It was the standard for the Atari 8-bit family of home computers and was compatible with the VIC-20, Commodore 64, Commodore 128, MSX, and later the Atari ST and Amiga. Third-party adapters allowed it to be used on other systems, such as the Apple II, TI-99/4A, and the ZX Spectrum.
