The voltage stabilizer protected from short circuits of an exit

In drawing is given by font face the circuit of the tranzitorny parametrical stabilizer in the compound regulating transistor T2, T3 with the device of protection against short circuits of an exit on the T1 transistor. Rated entrance voltage of this stabilizer 21 B, current of loading 0,3 And, range of change of target tension 2... 12 Century

the Device of protection work with font as follows. On base of the T1 transistor stable tension of shift in size about 1,7 In from diodes D1 and Д2 (are used as stabistor) is submitted. Together with the R1 resistor they form a divider of entrance tension. For lack of an exit overload the T1 transistor is closed, as the potential of its base concerning the emitter is positive. At short circuit of an exit the emitter of the T1 transistor becomes isolated on "the general plus". Thereof the potential of its base concerning the emitter becomes negative, and the transistor opens. Its collector current passes on the R2 resistor, power failure on it increases, negative shift on the basis of the T2 transistor sharply decreases and the compound regulating transistor passes to a condition close to a condition "is closed". Thus, the current of short circuit is limited. As soon as short circuit of loading will be liquidated, the base of the T1 transistor again will receive positive shift, and normal operation of the stabilizer will automatically be restored.