There are two switches: one has a contact rating of .5A @ 50VDC and the other is .3A @ 125VAC. I am aware that ratings of all sorts are somewhat "iffy," but what I am wondering is there a way to determine what current the contacts would handle at 5VDC.

Thanks.

 

Usually they have a rating that gives and idea.
http://en.wikipedia.org/wiki/NEMA_contact_ratings
Also there is Dry Contact types where the contacts cannot switch the primary current, IOW only open or close when the load is not present.
As a general rule, even if going with a lower DC voltage say, IMO, it is not always advisable to go any higher in current.
Max.

 

.5A

 

.5A

Is that your answer for both switches? Thanks.

 

For the DC rated switch. Don't think you can extrapolate DC ratings from the minimum AC ratings you gave for the other one. Look at manuf specs.

 

The fact of whether it is switching a resistive or inductive load factors in to a large degree also.
Max.