Primary Current Injection Set is a micro-controller based device used to check that the protective circuits or devices function correctly. Ajit Electronics Co. Supplies Primary Current Injection Set. Ajit Electronics Co. Is the manufacturer of electronics or electrical testing and measuring instruments like Transformer oil test sets, Spark tester, current injection sets, Relay test sets, Million mega ohm meters, Oil filtration plant and Transformer ratio meter. The Primary Current Injection Set is designed to deliver low impedance with a controlled and measured heavy current.