These are all generic terms for a component whose spring-loaded tip provides a reliable electrical contact to a target whose distance may be indeterminate. The traditional use for them is to make contact with printed circuit boards (PCBs) or electrical components to test functionality and measure component values. They are widely used in vacuum test fixtures associated with automatic test equipment (ATE). They are also used inside a functional test station as part of a larger production line.
The test probe comprises a metal tube, ready-assembled with a spring and contact plunger, supplied as a one-piece item. They are usually gold-plated because gold is an excellent electrical conductor and is corrosion-resistant. The electrical cable is generally connected to a receptacle which the test probe inserts into. The use of a receptacle allows the test probe to be removed for cleaning or replacement without disconnecting the electrical cable (see illustration below).
