Analysis of the principles of Zener diode circuit and Zener diode voltage stabilization circuit

The simplest voltage stabilizing circuit consists of a voltage stabilizing diode as shown in the figure. It can be seen from the characteristics of the Zener diode that if the Zener diode can always work in its voltage stabilization area, VO. will be basically stable around Vz.

 When the grid voltage increases, if the output voltage is to be kept constant, the voltage drop across the resistor R should increase, that is, the current flowing through R increases. This increased current is accommodated by the Zener diode, and its operating point will move from point b to point C. It can be seen from the characteristic curve that Vo≈Vz remains basically unchanged.

If the load resistance of the Zener diode voltage stabilizing circuit becomes smaller, the output voltage needs to remain unchanged and the load current needs to become larger. VI remains unchanged, and the current flowing through the resistor R remains unchanged. The increased current of the load is regulated by the voltage regulator tube, and its operating point will move from point b to point a. , the voltage regulator tube can be considered to adjust the current flowing through itself (the terminal voltage is basically unchanged) to meet the change of the load current, and cooperates with the current limiting resistor R

Convert changes in current into changes in voltage to adapt to changes in grid voltage. There is a problem with the voltage stabilization of the Zener diode circuit: when the grid voltage remains unchanged, the load current changes within the adjustment range of IZ (tens of mA), which limits the change range of the load current I0. How can we expand the range of changes in IO?