A terminal is the point at which a conductor from a

component Circuit Component may refer to: •Are devices that perform functions when they are connected in a circuit. In engineering, science, and technology Generic systems * System components, an entity with discrete structure, such as an assem ...

, device or

network Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematics ...

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 Network analysis can refer to: * Network theory, the analysis of relations through mathematical graphs ** Social network analysis, network theory applied to social relations * Network analysis (electrical circuits) See also *Network planning and ...

, ''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 capable of either generating electrical energy from chemical reactions or using electrical energy to cause chemical reactions. The electrochemical cells which generate an electric current are called voltaic o ...

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 air). Electrodes are essential parts of batteries that can consist of a variety of materials de ...

s) which are referred to as the

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

and

cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...

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. A common apparatus ...

such as a common AA battery, electrons flow from the negative terminal to the positive terminal, while the

conventional current An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving ...

is opposite to this.

Types of terminals

* Connectors *

Line splice In telecommunications, a line splice is a method of connecting electrical cables (electrical splice) or optical fibers (optical splice). Splices are often housed in sleeves to protect against external influences. Splicing of copper wires T ...

s * Terminal strip, also known as a tag board or tag strip *

Solder Solder (; NA: ) is a fusible metal alloy used to create a permanent bond between metal workpieces. Solder is melted in order to wet the parts of the joint, where it adheres to and connects the pieces after cooling. Metals or alloys suitable ...

cups or buckets *

Wire wrap Wire wrap is an electronic component assembly technique that was invented to wire telephone crossbar switches, and later adapted to construct electronic circuit boards. Electronic components mounted on an insulating board are interconnected by l ...

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 re ...

s *

Screw terminal A screw terminal is a type of 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 the wire by a screw, o ...

s and terminal blocks *

Wire nut Twist-on wire connectors are a type of electrical connector used to fasten two or more low-voltage (or extra-low-voltage) electrical conductors. They are widely used in North America and several European countries in residential, commercial ...

s, a type of twist-on wire connector *

Lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

s on electronic components *

Battery terminal Battery terminals are the electrical contacts used to connect a Electrical load, load or Battery charger, charger to a single cell or multiple-cell Battery (electricity), battery. These terminals have a wide variety of designs, sizes, and featu ...

s, often using screws or springs *

Electrical polarity An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving pa ...

References

{{Reflist Electronic engineering Electrical components