The HYGK-306A Circuit Breaker Tester is my company designed to meet the need of onsite test the dynamic characteristics of High-Voltage Circuit Breakers . It takes the ARM7 unit for core to sample, process and output; the main characteristic is that it's operated in alt. It has many advantages such as intelligence, multi-function, accurate data, strong anti-jamming, easy operation, small size, light weight ,beautiful appearance, etc. It can test the circuit breakers as follows: indoors or outdoors circuit breakers with less oil or more oil, vacuum circuit breakers, SF6 circuit breakers and so on.