I also have a tool I made years ago where you wind wire in a loop of so many turns and tape it together. Its of a certain size wire that you hook in series with the circuit and then put an inductive clamp from an amp meter around that wire as it will multiply the reading. But I have used my Fluke 10 amp scale for at least 20 years as I feel its more accurate and it has a protection fuse that will blow if you put to much current through it. I have always been careful using mine as like I said I feel its much more accurate when reading milli-amps of draw. But the other ways can work ok if you do it right. Good luck , Ron