Getting Down to Earth

摘要

My first job out of college was as a development engineer for a company that made large industrial motor drives up to 1,000 HP. I worked in a laboratory that had many prototypes and breadboards out in the open on top of work benches. Most of the circuits were powered from 240V or 480V AC power lines. One day I was working on a drive that was acting erratic, so I decided to look at the gate drive waveform with an oscilloscope. As I connected the clip lead of the scope probe to the gate drive circuit board, I was temporarily blinded by a flash of light. When I could see again, I found that the palm of my hand was black and slightly burned. The probe clip lead was gone as were most of the copper foil traces on the printed circuit board. I was very lucky in that my injuries were minor and short lasting.