Quick ? on DC power plugs

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

Reply to
Dave
Loading thread data ...

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-

--
====================================================================
John A. Weeks III            952-432-2708         john@johnweeks.com
 Click to see the full signature
Reply to
John A. Weeks III

Ahh. Yes. I can see that. Thanks for the illumination.

Dave snipped-for-privacy@hotmail.com

noticed

put

The

third

Reply to
Dave

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.

--
John G

Wot's Your Real Problem?
Reply to
John G

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.

Reply to
Mjolinor

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

Reply to
Dave

to

THREE?

can

Gotcha. Didn't think of that before. Thanks,

Dave snipped-for-privacy@hotmail.com

Reply to
Dave

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.