I have the $5/dozen Ebay and Radio Shack variety made in China and have wasted half an hour chasing an open circuit only to find my test lead has too much resistance or is open. Any suggestions for a quality brand online?
A lot of the cheap alligator clips improperly "crimp" the wire to the alligator clip leading to a poor connection. I put crimp in quotes because they actually just crush the alligator clip body around the wire AND insulation leading to just a pressure fit instead of a cold weld of a proper crimp.
Many years ago (more than ten) I bought a set of Mueller clips that were good quality and the wires were actually soldered to the clip. They look like the ones pictured here:
https://www.mouser.com/ProductDetail/Mueller-Electric/80120?qs=y6ZabgHbY%2Byx8bdTNKfmiw==
Unfortunately, the datasheet in the above link shows what appears to be your generic bad quality clip with a "pressure" fit so I fear the quality may not be what it once was :-(.
If you do gamble on a set of Mueller clips however, either the set of 5 above or the set of 10 here:
https://www.mouser.com/ProductDetail/Mueller-Electric/BU-00287?qs=MKfBgOLYr9DERPDsh/qDDA==
please let us know if the wire to clip connection is soldered or not.