普通熔丝对电路的过电流反应是较迟钝的，因而不能作为灵敏的保护装置，电子保护电路具有高速断流、恢复容易的特点，可应用于任何直流电路中作为保护装置。电子保护电路如图１，当Ｋ接通时，单向晶闸管３ＣＴ导通，直流电路导通，当用电量增大到超过它的允许值时，检测电阻Ｒ Ordinary fuses are relatively insensitive to the overcurrent response of the circuit, and therefore cannot be used as a sensitive protection device. The electronic protection circuit has the characteristics of high-speed shutdown and easy recovery, and can be applied to any DC circuit as a protection device. The electronic protection circuit is shown in Fig. 1. When K is turned on, the unidirectional thyristor 3CT is turned on and the DC circuit is turned on. When the power consumption increases beyond its allowable value, the detection resistance R