Active and passive input self-adaptive circuit for relay protection testing device

The invention relates to an active and passive input self-adaptive circuit for a relay protection testing device. The active and passive input self-adaptive circuit is characterized by consisting of a DC-DC (Direct Current-Direct Current) isolating power supply, an asymmetric bridge rectifier circuit and a photoelectric coupler circuit, wherein the DC-DC isolating power supply supplies a power supply to an input circuit; the photoelectric coupler circuit is used for transmitting the real-time state of the input at the strong current side to the weak current side, and a master control circuit at the weak current side monitors the real-time state; the asymmetric bridge rectifier circuit is used for converting a voltage with active input into a voltage with fixed polarity, so as to realize polarity self-adaption of the active input; an upper bridge of one bridge arm of the asymmetric bridge rectifier circuit and a lower bridge of another bridge arm are connected in series through three high-speed diodes, and each of another two bridges only comprises one high-speed diode. The active and passive input self-adaptive circuit disclosed by the invention is self-adaptive for various types of input forms and the polarity with active input. The invention is applicable to the active and passive input self-adaptive circuit for the relay protection testing device.