What is the specific principle of adding two resistors and two transistors to the resistor step-down circuit in the figure?

These two transistors seem to be 400V withstand voltage tubes. The purpose here is one-stage step-down and one-stage regulation. One such transistor is used in a 220Vac circuit, which has the risk of withstand voltage.

    When the circuit meets certain conditions, it can be used - when the load is 0, two 47K chips have certain risks. At full load, two 56K particles have a greater risk of breakdown (two particles should be connected in series with about 15K or three particles in series with appropriate resistance). The specific safety range needs to be calculated.

Connect in series, 56K*2 in parallel, two tubes, share the total pressure drop, and share some of the tube withstand voltage and power consumption.

This is not a resistance-capacitance step-down voltage, the resistance-capacitance step-down capacitors are in series. This feeling is to use a transistor to build a high-voltage LDO.

The triode switch functions, and the resistor divides the voltage of the triode.