I found a Japanese ammeter from WW2. It has a zero center, + - 10 A scale, with a green line on both sides at the + and - 3 A marks. So what would this be for, do you suppose? I would almost think vehicle battery, but 10A is not enuff current for that, under full charging, or headlamps on. And what about the 3 amp marks? tnx, Hue Miller