Twin wire with two insulated conductors laid parallel under an outer, nonmetallic covering.
Data Access Arrangement. DAA is used to translate the incoming and outgoing signals through phone line. Each country uses a different protocol, so a device that can interpret these signals is required.
Two or more connectors linked together by data bus wire.
The effect that light has on breakdown voltage. Higher ambient light levels produce lower breakdown voltages. If a neon lamp is to be operated in total darkness it is usually necessary to simulate ambient light by the addition of a small amount of radioactivity.
A two transistor amplifier connected so that its amplification equals the products of the two individual transistors.
In fiber optics, an optical wave guide used as a common trunk line, to which a number of terminals can be interconnected through optical couplers.
See also Daisy Chain.
A compilation of technical information on a specific device or component that defines the electrical and mechanical characteristics of that device or component.
Rate at which data is read from or written to a disc drive once the read/write head is in position.
Usually a smaller P.C. board that connects in the vertical plane to the main motherboard.
See Decibel.
Optical power expressed in decibels referring to 1 milliwatt, ie: 0 dm = 1mW
Direct Current
See Current, Direct.
Digital Cross-connect System
See Digital Cross-connect System.
See Resistance.
Data Display Channel. A standard configuration of D-Sub established by VESA (Video Electronics Standards for Applications). In the DDC configuration, pin #9 is moved back by 0.05" to enable hot plugging and unplugging of the equipment on the computer.
The various methods used to protect contacts when not engaged. The most common method uses a cover on the mating ends of connectors, which automatically covers the contacts when the connectors are separated.
Mating surface of a connector designed so that the contacts are recessed below the surface of the connector insulator body to prevent accidental short-circuiting of the contacts.
Display in which the switch button is translucent and individual pilot lamps illuminate it with various colors and legends.
An electric current that provides a single steady output signal to eliminate contact bounce by latching on at the initial contact closure.
A device or circuit which changes coded digital information into a commonly understood form.
A process in which a set of signals is translated into a single equivalent or representative value.
Digital European Telecoms standard for office cordless telephony backed by ETSI, the European Telecoms Standards Institute. Ericsson, Alcatel and Philips prefer DECT. Proponets claim DECT has the advantage of heavy use within an office building over CT2. CT2 is preferred by Northern Telecom and GPT.
See also CT2.
Any nonconformance with the normally accepted characteristics for a unit.
A gradual deterioration in performance. Also called Drift.
An artificial or real transmission line or equivalent device designed to delay a wave or signal for a specific length of time.
The electrolytic transfer of metal from one conductor to another. Similar to electroplating except the dendritic growth usually, though not always, forms from cathode to anode. The dendrite resembles a tree in appearance, and when it touches the opposite conductor, there is an abrupt rise in current, as in an electrical short.
Depletion Layer (Interfacial Junction)
The interfacial junction between two different semiconductor material types that creates a depletion layer having "dipoles" that create the polarity of charge across the layer. The barrier potential is the electrostatic field strength of the depletion layer. The layer is termed depletion since it is a charge carrier free zone, separating the "dipoles" of charge that have left or depleted that zone to enter into the two different semiconductor material types, respectively.
See also Barrier Potential, Diode, Semiconductor Material.
Process of applying a material to a base via vacuum, chemical, electrical, screening or vapor methods.
The distance the identor penetrates into the barrel. It is measured by gauging the thickness of the crimped portion of a contact between two opposite points on the crimped surface.
The value of operating current upon which the end-of-life figures are based in a lamp.
The amount of slug or excess material discarded from the necessary voids/holes created in the stamping process. It is determined at time of product/tool design and cannot be changed without major modifications. Scrap averages about 40-50% of total raw material used.
Any telephone designed to be operated while resting on a desk or other horizontal surface.
A desktop computer is a personal computer that is designed to fit conveniently on top of a typical office desk. A desktop computer typically comes in several units that are connected together during installation: the Processor, which can be in a micro-tower or mini-tower designed to fit under the desk or in a unit that goes on top of the desk, the Display Monitor, and the Input Devices, usually a keyboard and a mouse.
Process of disassembling soldered parts in order to repair, replace, inspect, or salvage them. Typical desoldering methods are wicking, pulse vacuum (solder sucker), heat pull, and solder extraction.
A German standards organization that develops standards for DIN connectors.
See also DIN.
An individual electrical element, usually in an independent body, which cannot be further reduced without destroying its stated function.
A condition in which liquid solder has not adhered intimately to an area and has pulled back from the base metal, leaving the base metal exposed.