I was thinking about replacing the DC power plug on something when I noticed that both the one I am was about to take out and the one I was about to put in have three solder contacts where they meet the PC board. Why THREE? The jack and plug both only have two contacts, for + and - so what's the third solder contact for?
Thanks,
Dave snipped-for-privacy@hotmail.com
The outer sleve of the jack often has two legs that solder to the circuit board. This is to give it a bit more mechanical strength.
-john-
Ahh. Yes. I can see that. Thanks for the illumination.
Dave snipped-for-privacy@hotmail.com
noticed
put
The
third
something when I
one I was about to
board. Why THREE?
so what's the
solder to the
strength.
Most DC sockets have a built in switch to disconnect the internal battery if required when the external plug is inserted. Try some continuity checks on the new plug and socket with the plug in and the plug out.
noticed
put
The
third
It is also common to find continuity between two of the connectors when no plug is in but open circuit when a plug is inserted. This is so that you can detect the plug and, for example, switch from battery power to mains.
Doesn't matter now. Went to the local parts depot and picked up an adapter that will fit the plug that's in there. No longer a problem. Thanks anyway.
Dave snipped-for-privacy@hotmail.com
to
THREE?
can
Gotcha. Didn't think of that before. Thanks,
Dave snipped-for-privacy@hotmail.com
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