A terminal is the point at which a conductor from a

component Component may refer to: In engineering, science, and technology Generic systems *System components, an entity with discrete structure, such as an assembly or software module, within a system considered at a particular level of analysis * Lumped e ...

, device or network comes to an end. ''Terminal'' may also refer to an

electrical connector Components of an electrical circuit are electrically connected if an electric current can run between them through an electrical conductor. An electrical connector is an electromechanical device used to create an electrical connection between ...

at this endpoint, acting as the reusable interface to a conductor and creating a point where external circuits can be connected. A terminal may simply be the end of a wire or it may be fitted with a connector or

fastener A fastener (US English) or fastening (UK English) is a hardware device that mechanically joins or affixes two or more objects together. In general, fasteners are used to create non-permanent joints; that is, joints that can be removed or disman ...

. In network analysis, ''terminal'' means a point at which connections can be made to a network in theory and does not necessarily refer to any physical object. In this context, especially in older documents, it is sometimes called a pole. On circuit diagrams, terminals for external connections are denoted by empty circles. They are distinguished from

node In general, a node is a localized swelling (a "knot") or a point of intersection (a vertex). Node may refer to: In mathematics * Vertex (graph theory), a vertex in a mathematical graph *Vertex (geometry), a point where two or more curves, lines ...

s or junctions which are entirely internal to the circuit and are denoted by solid circles. All

electrochemical cell An electrochemical cell is a device that either generates electrical energy from chemical reactions in a so called galvanic cell, galvanic or voltaic cell, or induces chemical reactions (electrolysis) by applying external electrical energy in an ...

s have two terminals (

electrode An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or a gas). In electrochemical cells, electrodes are essential parts that can consist of a varie ...

s) which are referred to as the

anode An anode usually is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, which is usually an electrode of the device through which conventional current leaves the devic ...

and

cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device such as a lead-acid battery. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. Conventional curren ...

or positive (+) and negative (–). On many dry batteries, the positive terminal (cathode) is a protruding metal cap, and the negative terminal (anode) is a flat metal disc . In a

galvanic cell A galvanic cell or voltaic cell, named after the scientists Luigi Galvani and Alessandro Volta, respectively, is an electrochemical cell in which an electric current is generated from spontaneous oxidation–reduction reactions. An example of a ...

such as a common

AA battery The AA battery (or double-A battery) is a standard size single cell cylindrical Dry cell, dry battery. ANSI and IEC battery nomenclature gives several designations for cells in this size, depending on cell features and chemistry. The Battery nom ...

, electrons flow from the negative terminal to the positive terminal, while the conventional current is opposite to this.

Types of terminals

* Connectors * Line splices * Terminal strip, also known as a tag board or tag strip * Solder cups or buckets *

Wire wrap Close-up of a wire-wrap connection Typical wire wrap construction of crossbar_switch.html" ;"title="Bell System telephone crossbar switch">Bell System telephone crossbar switch. Some types of connection were soldered. Wire wrap is an electron ...

connections (wire to board) * Crimp terminals (ring, spade, fork, bullet, blade) * Turret terminals for surface-mount circuits *

Crocodile clip Alligator clip A crocodile clip or alligator clip is a plier-like spring-tensioned metal clip with elongated, serrated jaws that is used for creating a temporary electrical connection. This simple mechanical device gets its name from the r ...

s *

Screw terminal A screw terminal is a type of terminal (electronics), electrical connection where a wire is held by the tightening of a screw. Description The wire may be wrapped directly under the head of a screw, may be held by a metal plate forced against ...

s and terminal blocks * Wire nuts, a type of twist-on wire connector *

Lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

s on electronic components * Battery terminals, often using screws or springs *

Electrical polarity The following Outline (list), outline is provided as an overview of and topical guide to electrical polarity (also called electric polarity). Positive and negative polarity * In electrical engineering, electrical polarity defines the direction ...

References

{{commons category Electronic engineering Electrical components

Types of terminals

See also

References