Finding Contacts for Circular Connectors

Searching for contacts for a circular connector can be challenging. With a little luck, this post should help simplify the process.

While Digi-Key does try to create a list of associated items for the circular connector housings we carry, we do not have them all covered, especially mil-spec connectors. So let’s look at a mil-spec connector for reference 2403-MS3476L12-10P-LC-ND.

The key to unlocking this process is in the shell size of the connector which is listed in the “Product Attributes” on the Digi-Key product page. The part number we are using as an example has a 12-10 shell size. Once the shell size is known, the next step is to find the contact size in the manufacturer catalog which is almost always linked on the product page on the Digi-Key website under “Documents and Media.” This is usually listed with the contact/insert arrangement information, page 123 in this case. (

From here we can determine that there are ten, size twenty contacts in this connector. Once the size of the contacts is known the table for the contact part number is usually just a couple of pages back. In this case, just two pages back on page 121.

While this certainly doesn’t make the process fool proof, once one knows what to look for, after just a few practice runs it does become pretty quick and easy to find what you need. To summarize, first find the shell size, from there find a listing of contact/insert arrangements in the manufacturer catalog which will list the contact size based on that shell size, then find the contact listing which is almost always near the end of the catalog and find the part number based on contact size.

If there are any questions or suggestions on this process please feel free to reply to this post and we will be happy to address them.