# Wall wart power plug jack size?

#### spinnaker

Joined Oct 29, 2009
7,835
I have a couple of wallwarts. I need to know what size jack that I need for the plugs on the wallwart.

The one should be easy in that Radio Shack carries it. I bought it before. What is a little confusing is that the OD of the plug measures .22 mm but the Radio Shack one measures .25 mm. I realize a small difference but that makes it harder to size my second jack.

It measures .137 mm OD The inside hole where the pin goes measures .049 mm but it is very hard to measure accurately as it is hard to get the caliber in there.

I found the wallwart online here. But I could not find specs.

#### #12

Joined Nov 30, 2010
18,210
You really need to get your millimeters sorted out. You are asking about things that are 5 to 8 thousandths of an inch O.D.

#### spinnaker

Joined Oct 29, 2009
7,835
You really need to get your millimeters sorted out. You are asking about things that are 5 to 8 thousandths of an inch O.D.

Duh! I guess I have not woken up yet this morning. And metrically challenged!.

OK 2nd try. The big on measures 5.46 O.D. mm but the Radio Shack one that fits is a 5 mm O.D.

The small one measures 3.40 O.D. With the inside hole around 1.27 mm.

#### spinnaker

Joined Oct 29, 2009
7,835
http://en.wikipedia.org/wiki/Coaxial_power_connector

Or this.

See the chart toward the bottom of the page.

Thanks. That is exactly what I was looking for!

I stopped at Radio Shack. course they did not have the jack but they had a bunch of plugs. We sized them up and it looks like it might be size G. That seems to be confirmed by the chart.

There is no way to confirm because they did not have the jack.

If I could just figure out a way to accurately measure that interior hole.

#### SgtWookie

Joined Jul 17, 2007
22,220
Kind of an expensive solution, but numbered drills (used in machine work, most frequently for drilling prior to creating threads or drilling out existing threads) are a pretty good way to get sizes. Inside calipers are another method. I bought an 8" digital caliper from Harbor Freight for around $15 on sale a few years back. Thread Starter #### spinnaker Joined Oct 29, 2009 7,835 Kind of an expensive solution, but numbered drills (used in machine work, most frequently for drilling prior to creating threads or drilling out existing threads) are a pretty good way to get sizes. Inside calipers are another method. I bought an 8" digital caliper from Harbor Freight for around$15 on sale a few years back.
I have an inside caliper but I don't think I can reach all the way inside, with the caliper I have. I am measuring 1.25 mm I.D. Not sure how accurate that is. Plus I am using a cheap Harbor Freight caliper.

#### tracecom

Joined Apr 16, 2010
3,944
I guess you don't need this anymore, but someone else might. I put it together some time ago.

#### Attachments

• 13.9 KB Views: 57