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Complete Guide to Banana Test Sockets (Jacks)

26 November 2018 16:20


The Complete Guide to Banana Test Sockets (Jacks)

A banana test socket or banana jack (US terminology) is a female electrical connector used to safely connect a single-wire/ lead to electronic or electrical test equipment, instruments or other apparatus. Within Europe they are manufactured and tested to meet the requirements of the European Low Voltage Directive (LVD) 2006/95/EC and should also meet the standards of IEC 61010 Safety requirements for electrical equipment for measurement, control, and laboratory use. There are a number of types of female electrical connectors such as banana sockets or jacks, binding posts and dual plugs and sockets.  We’ll explain the common connectors and examples of typical applications below. 

1 - General Information On Banana Sockets (Test Jacks)

2 - Types of Banana Sockets (Jacks)

3 - Types of Binding Posts

4 - Dual Banana Test Sockets and Posts


1 - General Information on Banana Sockets (Jacks)?

Most banana sockets (jacks) are commonly found with either a 4mm or 2mm socket, that accepts a 4mm or 2mm sized banana plug. You can view our quick guide to banana plugs here. They can also be found in 1mm variants and often known as 'pin sockets' when of this size.

Banana sockets (Jacks) can be found in a range of colours, the most common being black and red, and it is normal for them to conform to the standard colour codes; 0 - Black, 1 - Brown, 2 - Red, 3 - Orange, 4 - Yellow, 5 - Green, 6 - Blue, 7 - Violet, 8 - Grey, 9 - White

Types of Female Electrical Connectors

2 - Types of Banana Sockets

A banana socket or jack is the name given to the female connector that a banana plug is inserted into.  They are normally mountable to fit in an enclosure or on a panel so that the main socket face rests on the surface of the enclosure or panel. The socket (jack) may have different kinds of connection terminals on their rear end which allows them to connect to many different electrical items or circuits. Below is a list of different terminal types;

1. Studded

2. Faston Terminal (Spade)

3. Pin

4. Lug

Where are Banana Sockets (jacks) commonly used? 

Banana sockets (jacks) are commonly found mounted on panels of industrial equipment or within Multimeters, Oscilloscopes and other electrical testing instruments. They are used to to accept test leads or other cables and make connections between an item under test, measurement or to join parts of a circuit.  Banana sockets are common across many electrical or electronic related fields whether it’s industrial process right the way through to Automotive diagnostics.

   3265-I Banana Socket – M4 Stud          3266-I Banana Socket – Faston Terminal       3267-I 4mm Safety Banana Socket

PJP 3265-I Banana Jack   PJP 3266-I Banana Jacks    PJP 3267-I 4mm Banana Jack


3 - Types of Binding Posts

The binding post is a connector consisting of a threaded screw to which bare wires are attached and held in place by a nut. Binding posts can be called a “5-way” or “universal” post because there are 5 ways to attach a wire to it:

1. Banana Plugs via a socket in the screw top.

2. Pin Connectors via the hole in the post or a socket in the screw top.

3. Bare Wire via a hole in the post.

4. Lug Terminal by inserting the lug between the screw top and base.

5. Alligator Clip via clipping onto the post.

Where are binding post Terminals commonly used? 

Binding post terminals are typically found on; speakers, receivers, high-voltage test equipment and various test and measurement hand held devices. 

      3760 4mm Binding Post                     4995 Spring Loaded Binding Post                     3770 4mm Binding Post

PJP 3760 4mm Binding Post   Spring Loaded Binding Post  Gold Binding Post Terminal


4 - Dual Banana Jacks and Posts

Dual Sockets are simply two sockets together that make it safer to plug in two wires with no chance of stray wire strands creating a short across contacts. Similarly, dual binding posts are two posts together that commonly have a dual plug inserted.

Where are dual Banana Sockets (Jacks) and posts commonly used?

Dual Banana Sockets and posts are typically found in amplifiers or speakers that use traditional binding posts. Dual double binding post with BNC connectors are used for miniature-to-subminiature coaxial cable in radio, television, and other radio-frequency electronic equipment, test instruments such as automotive oscilloscopes, and video signals.   

    9407 Double Binding Socket                1296 BNC Plug to Double Binding Post

Double Binding Socket Terminal  BNC Plug to Double Binding Post Terminal



Banana sockets are a common and important component in many electrical applications. Joining wires and leads to equipment correctly is invaluable for safety and performance. Be sure to choose the correct; type, terminal style, colour and size for your electrical application. If you are still unsure after reading our guide please get in contact and we’ll be happy to advise you.

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