Spring Contact Test Probes

Spring Contact Test Probes are equipment which is used as test connector-cable systems. These equipment create an electrical connection between the object to be tested and the testing system. Primarily deployed for electrical testing of connectors, printed circuit boards, cables, and various other electrical components and assemblies these instruments prove instrumental in the connection between two electrical circuits or boards.

These contact probes are made up of a tubular barrel, a spring and a plunger. There are many varieties of tip styles and different spring pressures that ensure the best contact with the test surface. Spring contact probes are suitable for all contacting in two terminal measurements which does not require tolerance compensation. 

Benefits of Spring Contact Test Probes

•    Small initial outlay

•    Contact can be changed quickly

•    Ideally suited for signal lines and currents

•    Contact Spacing from 0.4 mm

•    Low maintenance costs

•    Available with floating mounting on request

•    Extensive standard product range.

These probes are available for various applications:

Used as a threaded probe to provide a secure fit. Used for the test of wire harnessing.

Used for high current applications and designed for very small probe resistance.

These probes can be used as special probes with integrated switch elements, mainly used for presence.

Radio frequency probes – Special spring contact probes are used to transmit high-frequency signals. These probes have an inner conductor for the transmission of the signal and an outer conductor for shielding.

Flying Probe Test Systems

Flying probe tester is a form of automated test equipment that has been in use around 1986 when the first testers were introduced. Flying probe testers provide many advantages over other forms of automated test equipment for particular application and purpose. In the initial days flying probe testers were introduced to cover the prototype and very small quantity production areas. Now the use of this type of automated test equipment has expanded, and although not used as the main test in high volume production, they are nevertheless used in many areas.

Flying Probe

The concept of flying probe test system is that rather than having a comprehensive fixture for a given PCB assembly that can access all the required nodes via a “bed of nails”, the system uses a generic board holder, and one or more probed moves across the board accessing individual nodes under software control. The flying probe tester is therefore able to cut down on the number of test fixtures that are required and it’s easier to introduce changes, especially to features such as component or pad positions because it is just a matter of changing the software controls.

Advantages of Flying Probe Tester

No special EOL Fixture required: The probes move accordingly under software control to make contact with the required nodes, the “bed of nails” and the fixture requirement is not needed. Rather a simple generic mechanism to hold the board in place is needed.

Changes can be made easily: Due to the presence of software control the pads also move accordingly and do not require manual handling. It is not required to make any mechanical changes to the fixture.

Test Development time is not needed: Time is easily saved because the first and foremost thing that has been put off is the mechanical requirement that is not carried out. Due to the availability of software control it is done easily.     

Disadvantages of a flying probe:

Speed is slow – The flying probe is relatively slow as compared to as compared to other forms of automated test equipment such as an ICT because the probes have to physically move to each position in turn.

Complicated tests are not easy to perform through a flying probe. It is necessary to check the performance of the individual flying probe tester to ensure it can meet the requirements.