I'm looking for some help identifying what the reference designator 'E' on this Logic board is for.
Can these pads be used as test points when trying to find a fault?
The board is from a Datamax O'Neil / Honeywell industrial printer (I-4212e)
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3 Answers
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It's a pad for a flying probe test (which happens at assembly and you can see indentations from a probe or meter, if this is a production board then it's probably a flying probe test point).
Flying probes are used mostly by PCB assembly services to test PCBs to make sure that the components have been installed correctly, and can be used to check things like conductivity or voltages to verify a PCB is working as the design intended.
Why they designate it with E is beyond me, and could probably only be answered by the designer. I think from experience many of the good designator letters are taken.
answered Jun 26, 2021 at 18:15
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2\$\begingroup\$ Merely thinking aloud: External or End-point? \$\endgroup\$ Jun 27, 2021 at 7:21
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\$\begingroup\$ I'm betting on end point, but I could see both \$\endgroup\$– Voltage Spike ♦Jun 27, 2021 at 22:15
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IEEE Std 315 suggests that you use "TP" for testpoints. The single letter "E" can be used for many things, including "circuit terminal", "electrical contact", or "terminal {individual)".
However, there's no reason to think that every manufacturer follows that standard in every detail. If you really want to know you should contact the manufacturer.
answered Jun 26, 2021 at 17:12
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Test point? That's the designation we use for such things.
Edit 1
Note, we also use "E" for the uses Elliot mentioned in his comment. I'm gonna venture a guess that someone along the way decided that "electrical contact" included test points.
