Overview
The terms plug and jack are commonly used when discussing test leads, connectors, instruments, and accessories. While these terms are sometimes used interchangeably in conversation, they refer to two different parts of a connector system.
Understanding the distinction can help identify the correct accessories, replacement parts, and connection points when reviewing documentation or contacting technical support.
What Is a Plug?
A plug is the male portion of a connector.
The plug contains the contact that is inserted into another connector to make an electrical connection.
Common examples include:
Banana plugs on test leads
Power cord plugs
Audio plugs
Example
Test Lead ----[ Banana Plug ]
↑
Male Connector
Key Characteristic
A plug is designed to insert into a jack.
What Is a Jack?
A jack is the female portion of a connector.
The jack receives the plug and provides the mating connection.
Common examples include:
Banana jacks on multimeters
Panel-mounted connectors
Audio jacks
Example
[ Banana Jack ] ---- Meter Input
↑
Female Connector
Key Characteristic
A jack is designed to accept a plug.
Banana Plug vs. Banana Jack
In test and measurement equipment, the distinction is typically straightforward:
| Component | Type | Typical Location |
|---|---|---|
| Banana Plug | Male | Test lead |
| Banana Jack | Female | Meter, power supply, calibrator, or panel |
Typical Connection
Test Lead Instrument
[ Banana Plug ] ----------> [ Banana Jack ]
Male Female
What Is a Banana Jack Lug?
The term banana jack lug occasionally appears in older documentation, parts lists, or customer discussions.
In most cases, this refers to a banana jack that includes a wiring termination lug on the rear side.
Example:
Front of Panel Rear of Panel
[ Banana Jack ] ------ [ Solder Lug ]
The word lug typically describes the wiring connection on the back of the jack and does not change the connector's function.
A banana jack with a lug is still a banana jack.
Common Source of Confusion
Customers may use the terms plug, jack, and lug interchangeably.
When clarification is needed, the following question often resolves the issue quickly:
Are you referring to the connector on the test lead (plug) or the connector mounted on the instrument (jack)?
This distinction generally identifies the correct component immediately.
Frequently Asked Questions
Is a banana plug the same thing as a banana jack?
No.
A banana plug is the male connector that inserts into a banana jack, which is the female connector.
Is a banana jack always mounted on an instrument?
Not necessarily.
While commonly found on meters, power supplies, and test equipment, banana jacks may also be mounted on panels, fixtures, or custom equipment.
What does the term "lug" mean?
A lug is typically a wiring termination point used to connect internal wiring to a connector. The presence of a lug does not change whether a connector is a plug or a jack.
Quick Reference
| Term | Connector Type | Description |
|---|---|---|
| Plug | Male | Inserts into a jack |
| Jack | Female | Receives a plug |
| Banana Plug | Male | Commonly found on test leads |
| Banana Jack | Female | Commonly found on instruments |
| Banana Jack Lug | Female | Banana jack with a rear wiring lug |