A binding post is a connector commonly used on electronic test equipment

Electronic test equipment

Electronic test equipment is used to create signals and capture responses from electronic Devices Under Test . In this way, the proper operation of the DUT can be proven or faults in the device can be traced and repaired...

 to terminate (attach) a single wire or test lead

Test probe

A test probe is a physical device used to connect electronic test equipment to the device under test . They range from very simple, rugged devices to complex probes that are sophisticated, expensive, and fragile.- Voltage probes :Voltage probes are intended to measure voltages on the DUT...

. They are also found on loudspeaker

Loudspeaker

A loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...

s and audio amplifier

Audio amplifier

An audio amplifier is an electronic amplifier that amplifies low-power audio signals to a level suitable for driving loudspeakers and is the final stage in a typical audio playback chain.The preceding stages in such a chain are low power audio amplifiers which perform tasks like pre-amplification,...

s as well as other electrical equipment.

A binding post contains a central threaded metal rod and a cap that screws down on that rod. The cap is commonly insulated with plastic

Plastic

A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

 and color-coded: red commonly means an active or positive terminal; black indicates an inactive (reference or return) or negative terminal; and green indicates an earth (ground) terminal.

Commonly designed in a style called five-way or universal, such binding posts allow the connection of several different types of connections:

• Banana plugs
  Banana connector
  A banana connector is a single-wire electrical connector used for joining wires to equipment. The term 4 mm connector is also used, especially in Europe, although not all banana connectors will mate with 4mm parts...
  
  , inserted into the open end of the binding post
• Pin connectors, inserted into a hole drilled through the metal post and clamped by the screw-down portion of the binding post.
• Bare wire
  Wire
  A wire is a single, usually cylindrical, flexible strand or rod of metal. Wires are used to bear mechanical loads and to carry electricity and telecommunications signals. Wire is commonly formed by drawing the metal through a hole in a die or draw plate. Standard sizes are determined by various...
  
   inserted through the same hole and clamped, or
• Wrapped around the metal post and clamped.
• A lug terminal inserted around the metal post and clamped.

"The original 5-WAY Binding Post " is and was a product of the Superior Electric Company of Bristol, Connecticut, USA. It was invented by Owen J. McCabe who was also responsible for many other Superior Electric products. Ref: http://www.danaherspecialtyproducts.com/Content.aspx?id=1225&terms=binding

The binding post was a commercial invention of the General Radio

General Radio

General Radio Company was a broad-line manufacturer of electronic test equipment. Started in Cambridge, Massachusetts in 1915, the company moved to West Concord in the 1950s. There, it became a major player in the automatic test equipment business, manufacturing a line of testers for assembled...

 Corporation.

Safety

Even so called isolated binding posts are typically not sufficiently isolated to protect users from coming into contact with their metal parts carrying voltage. As such they are not suitable to be used for carrying dangerous voltages (cf. Extra-low voltage). On several types of equipment it has been becoming common to no longer use the traditional binding posts, but safety banana jacks. The universal property of binding posts are lost here, since safety banana jacks can only be used with traditional and safety banana plugs.

In the past, it was common for multiple five-way binding posts to have their drilled holes lined up; this provided convenience in some applications as a bare wire could be strung from post to post to post. But this also impaired safety as two wires or pin connectors could be inserted from opposite sides of two binding posts and the tips of the wires or probes might inadvertently short together. Holes are now normally aligned in such a fashion that such shorts cannot occur.

Standard Distance

In order to permit the use of double banana plugs, the standard distance between the positive and negative plugs should be 3/4".

See also

• Fahnestock clip
  Fahnestock clip
  A Fahnestock clip is an early technology for a electrical terminal. It is still used occasionally in educational electronic kits and teaching laboratories in schools. It is designed to grip a bare wire securely, yet release it with the push of a tab. The clip was patented February 26, 1907by...
  
   — an earlier device, now largely supplanted by binding posts
• Banana connector
  Banana connector
  A banana connector is a single-wire electrical connector used for joining wires to equipment. The term 4 mm connector is also used, especially in Europe, although not all banana connectors will mate with 4mm parts...
  
  

External links

• About.com glossary definition