Quick ? on DC power plugs

D

Dave

Guest
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
db5151@hotmail.com
 
In article <c6uvat$6is@library2.airnews.net>, Dave <db5151@hotmail.com>
wrote:

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?
Click to expand...
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
Newave Communications http://www.johnweeks.com
====================================================================
 
Ahh. Yes. I can see that. Thanks for the illumination.

Dave
db5151@hotmail.com

"John A. Weeks III" <john@johnweeks.com> wrote in message
news:300420042119260899%john@johnweeks.com...
In article <c6uvat$6is@library2.airnews.net>, Dave <db5151@hotmail.com
wrote:

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?

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
Newave Communications http://www.johnweeks.com
====================================================================
Click to expand...
 
"Dave" <db5151@hotmail.com> wrote in message
news:c6vfdu$sif@library2.airnews.net...
Ahh. Yes. I can see that. Thanks for the illumination.

Dave
db5151@hotmail.com

"John A. Weeks III" <john@johnweeks.com> wrote in message
news:300420042119260899%john@johnweeks.com...
In article <c6uvat$6is@library2.airnews.net>, Dave
db5151@hotmail.com
wrote:

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?

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-
Click to expand...
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?
 
"John A. Weeks III" <john@johnweeks.com> wrote in message
news:300420042119260899%john@johnweeks.com...
In article <c6uvat$6is@library2.airnews.net>, Dave <db5151@hotmail.com
wrote:

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?

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.
Click to expand...
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.
 
"John G" <Greentest@ozemail.com.au> wrote in message
news:t2Ikc.293$Iq5.13166@nnrp1.ozemail.com.au...
"Dave" <db5151@hotmail.com> wrote in message
news:c6vfdu$sif@library2.airnews.net...
Ahh. Yes. I can see that. Thanks for the illumination.

Dave
db5151@hotmail.com

"John A. Weeks III" <john@johnweeks.com> wrote in message
news:300420042119260899%john@johnweeks.com...
In article <c6uvat$6is@library2.airnews.net>, Dave
db5151@hotmail.com
wrote:

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?

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-

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?
Click to expand...
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
db5151@hotmail.com
 
"Mjolinor" <mjolinor@hotmail.com> wrote in message
news:d3Ikc.14$tQ4.9@newsfe1-gui.server.ntli.net...
"John A. Weeks III" <john@johnweeks.com> wrote in message
news:300420042119260899%john@johnweeks.com...
In article <c6uvat$6is@library2.airnews.net>, Dave <db5151@hotmail.com
wrote:

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?

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.


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.
Click to expand...
Gotcha. Didn't think of that before. Thanks,

Dave
db5151@hotmail.com
 
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