Current type rotating speed signal input short circuit protection circuit

A current type rotating speed signal input short-circuit protection circuit comprises a turn-off circuit, a short-time current-limiting circuit, a voltage monitoring circuit and a signal detection circuit, the turn-off circuit is connected with the short-time current-limiting circuit, the short-time current-limiting circuit is connected with the voltage monitoring circuit and the signal detection circuit, the turn-off circuit comprises an NPN triode Q3, and the NPN triode Q3 is connected with the voltage monitoring circuit. The short-time current limiting circuit comprises an NPN triode Q1, an NPN triode Q2, a resistor R1, a resistor R2 and a resistor R3, the input end of the bus is connected with a capacitor C1, and the output end of the bus is connected with a capacitor C2. According to the utility model, the defects in the prior art are overcome, the circuit state is monitored in real time through closed-loop logic control, and the safety is good; the environment tolerance is high, and the reliability is h