A terminal is the point at which a conductor from a component, device or network comes to an end.[1] Terminal may also refer to an electrical connector at this endpoint, acting as the reusable interface to a conductor and creating a point where external circuits can be connected.[2][3] A terminal may simply be the end of a wire or it may be fitted with a connector or fastener.[citation needed]
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.[4] They are distinguished from nodes or junctions which are entirely internal to the circuit, and are denoted by solid circles.[5]
All electrochemical cells have two terminals (electrodes) which are referred to as the anode and cathode 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 such as a common AA battery, electrons flow from the negative terminal to the positive terminal, while the conventional current is opposite to this.[6]
Types of terminals
- Connectors
- Line splices
- Terminal strip, also known as a tag board or tag strip
- Solder cups or buckets
- Wire wrap connections (wire to board)
- Crimp terminals (ring, spade, fork, bullet, blade)
- Turret terminals for surface-mount circuits
- Crocodile clips
- Screw terminals and terminal blocks
- Wire nuts, a type of twist-on wire connector
- Leads on electronic components
- Battery terminals, often using screws or springs
- Electrical polarity