Why is a switching type power supply less expensive and lighter than an equivalent linear power supply?
The inverter design does not require an output filter circuit
The control circuitry uses less current, therefore smaller heat sinks are required
The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output✓Bonne réponse
It recovers power from the unused portion of the AC cycle, thus using fewer components
Explication
Transformer and filter component size shrinks as operating frequency rises. A switching supply converts to tens or hundreds of kilohertz before transforming, so its magnetics and capacitors are far smaller and lighter than those of a 50/60 Hz linear supply of the same output power.