✔ 最佳答案
An OHM Meter..
Some advice stay away from Radio Shack, 'Radio Crap', when you decide to buy your meter.....after all the invented the TRS80 computer generally refered to as the 'Trash 80'
They always blow up if you are on the wrong setting...like trying to measure 120 v and the meter set on Ohms.....
Cheap and no protection...fuses
參考: A childhood of sticking bobbi pins in electrical wall sockets