It is well known that power adapters sold in the United States need to pass UL certification, because the UL safety testing institute is the most authoritative in the United States, and it is also the largest private organization engaged in safety testing and identification in the world.

Key Differences Between Linear Supply and Switch Mode Power Supply

PD means Power Delivery, which is also the fast charging technology.

What is the power adapter? What is the charger? What is the relationship and difference between them?