After review from an AC to DC converter datasheet, I am very keen to understand the design of the circuit function ( refer to the attached circuitry)

1. If this circuit is a Linear or a switch-mode power supply?
2. Do not understand why it is initiated from AC to DC full-wave by then switch mode to AC and finally back to DC half-wave? Am I wrong about this scenario?

Thank you.

 

It's about the Frequency ..........
Mains AC Power is either 50 or 60hz,
to change or Regulate this relatively low Frequency requires
very large Filtering-Components.
As the Frequency goes up, everything gets smaller, and usually less expensive.
.
.
.

 

1. Switch-mode supply.
2. It reduces the size of the needed isolation/stepdown transformer because of the much higher switching frequency. The DC output filter requirements for DC ripple are also reduced.

https://www.monolithicpower.com/en/switching-power-supply

 

The power line (50 or 60hz) delivers power 100 or 120 time a second. It passes through a transformer and into filter capacitors and out.
A switching power supply delivers power through the small transformer about 120,000 time a second and into smaller storage capacitors.
Watch these boys caring 120 buckets a day. They could run at 3000 mile/hour caring a cup of water.

 

It's about the Frequency ..........
Mains AC Power is either 50 or 60hz,
to change or Regulate this relatively low Frequency requires
very large Filtering-Components.
As the Frequency goes up, everything gets smaller, and usually less expensive.
.
.
.

Thanks, I get the points.

 

1. Switch-mode supply.
2. It reduces the size of the needed isolation/stepdown transformer because of the much higher switching frequency. The DC output filter requirements for DC ripple are also reduced.

https://www.monolithicpower.com/en/switching-power-supply

I get your points and thank you for the Switching power supply reference, is a good one for me.

 

The power line (50 or 60hz) delivers power 100 or 120 time a second. It passes through a transformer and into filter capacitors and out.
A switching power supply delivers power through the small transformer about 120,000 time a second and into smaller storage capacitors.
Watch these boys caring 120 buckets a day. They could run at 3000 mile/hour caring a cup of water.
View attachment 246939

Thank you very much for your detailed example, you made me further understand this is a typical circuitry apply from the principle of the high the frequency the lower the capacitance.