Perkin-Elmer AD-1 first electronic micro-balance with closed servo-loop. Range 0-1gm. Perkin-Elmer AD-1 first electronic micro-balance, with closed servo-loop. Range 0-1gm. circa 1980
Perkin-Elmer AD-2Z second generation electronic micro-balance. Commercially very successful but has an auto-zero feature which was unpopular. Range 0-1gm. Perkin-Elmer AD-2Z second generation electronic micro-balance circa 1990