In the voltage stabilizing circuit in the figure, what is the detailed change process of the base and collector voltage of the transistor from 0V to a stable state when the power is turned on?

EEW2018

In the voltage stabilizing circuit in the figure, what is the detailed change process of the base and collector voltage of the transistor from 0V to a stable state when the power is turned on? [Copy link]

In the voltage stabilizing circuit in the figure, what is the detailed change process of the base and collector voltage of the transistor from 0V to a stable state when the power is turned on?

maychang

"In the voltage stabilizing circuit in the figure, when the power is turned on" "Power is turned on"? Do you mean that the input voltage suddenly changes from zero to Ui?

chunyang

Assume that the input power rises along a certain curve, and the final stable voltage is higher than the breakdown voltage of the Zener tube. The variation law of the transistor collector voltage is the variation law of the power supply voltage. The transistor emitter voltage and base voltage follow each other, with a difference of a PN junction voltage drop, which is about 0.7V for silicon tubes. Before rising to the Zener tube breakdown voltage, the transistor base voltage follows the rising curve of the power supply voltage. When it reaches the Zener tube breakdown voltage, the Zener tube breaks down, clamping the base voltage at its breakdown voltage.