A digital control circuit scheme used as protection and control for medium and low voltage switchgears is introduced in this paper. This scheme is of simple circuit construction

easy maintenance and testing

low cost for developing and producing.The experimental results show that the circuit possesses high accuracy

reliability and repeatability in the action.In the case of the medium or low voltage switchears which just require simple and cheap protection and control

this scheme is of superiority.The paper gives the construction and design idea of the circuit

test results of some protection properties as well.