Is the 40TPS12A thyristor in this power-on buffer circuit used to switch the resistor?

西里古1992

Is the 40TPS12A thyristor in this power-on buffer circuit used to switch the resistor? [Copy link]

What is the specific working principle? Why does one of the two power-on buffer circuits use so many filter capacitors, while the other only has one? Aren't the bus voltages the same after rectification?

chunyang

The thyristor is just a switch, and the power-on surge current is controlled by controlling its conduction period. The series connection of capacitors is to obtain a higher withstand voltage, and the parallel connection is to obtain a larger capacity. The first figure uses the method of switching the resistor by a relay to suppress the power-on surge.