Next, we must find an insert arrangement that meets or exceeds our contact requirements. At a minimum, the insert or contact arrangement must have the same number and size of contacts needed. It can, however, also contain additional unused contact positions that may provide options for future use.
After looking at the insert arrangements in the PM Series catalog (MIL-DTL-5015 style), we can see that the 18-9 insert has room for 5 x #16 contacts and 2 x #12 contacts. This insert will accommodate our 3 x #16 contacts and 2 x #12 contacts and leave us with two extra #16 contact positions. The extra positions give us the option of adding connections later and do not compromise the integrity of the connector in any way.
Summary
- The contact insert holds and protects the contacts
- The contact arrangement must meet or exceed your contact requirements
- The arrangement may contain unused contact positions if an exact match cannot be found