An effective source of direct current having any desired output up to 45 amperes at 150 volts is described, being characterized by small size, light weight, low cost, and negligible maintenance. While it has superseded all other d.c. sources, regardless of cost, in the Norton Company laboratories, it is particularly recommended where cost is an important consideration. It is also a useful auxiliary unit where highly refractory materials are analyzed regularly, since these materials are sometimes difficult to volatilize completely with the familiar multipurpose type of source. An automatic current controller is also described as a separate unit, and can be used to hold the current within ±0.5 ampere at any selected value between 5 and 15 amperes.
G. H. FETTERLEY and W. M. HAZEL, "A D.C. Arc Source and Automatic Controller," J. Opt. Soc. Am. 40, 76-78 (1950)