For years Greenlee has offered a device for testing HID and fluorescent bulbs. Milwaukee also offers one these days. What are they good for?
Well ....
I have a nephew, a certified geek with various degrees in physics. He was very concerned about EMF, and decided to get a gauss meter, so he could identify EMF issues in his home. Alas, he decided to do his EMF survey the day I was visiting ....
He gets out his meter, and I (quietly) got out mine. Every now and then I'd push my 'test' button, which would send his meter (across the house) off the scales. Before long, I had him critically studying a wastebasket, trying to determine how the simple plastic tub could be the source of so much EMF

He was completely amazed, puzzled, and finally fascinated with my meter. The idea of using EMF to test bulbs had him shaking his head in wonder. What will they think of next?
Maybe I'll 'invent' the sundial next
