5V stabilized voltage supply with protection?function

The invention discloses a 5V stabilized voltage supply with a protection function. The 5V stabilized voltage supply comprises a transformer, a switch, a fuse, a rectifier circuit, a bidirectional thyristor, a three-terminal regulator, a first diode, a second diode, a voltage-regulator tube, a light-emitting diode, a first capacitor to an eighth capacitor, and a first resistor to the fourth resistor. During normal operation, output voltage is 5V, and the bidirectional thyristor is in a cut-off state. When output voltage exceeds a limit value for some reason, breakdown happens to the voltage-regulator tube. Thus, voltage across the third resistor rises to trigger conduction of the bidirectional thyristor and cause fusing of the fuse so as to protect the loads. The stabilized voltage supply with the protection function adopts a collector output tandem type voltage stabilization mode, has characteristics of low cost, high efficiency, light weight, low ripple, high stability and the like, and has current-amplifica