Low-frequency transformers in microwave oven high-voltage circuits step up mains voltage to 2,000-3,000V, powering the magnetron to generate microwaves. Their core function is voltage conversion via electromagnetic induction, while isolating high/low-voltage circuits for safety.

Low-frequency transformers in isolated LED drivers convert AC mains to safe low-voltage DC, providing electrical isolation and voltage adaptation.

In an automotive welding workshop, PLCs control robotic arms and sensors. Grid voltage fluctuates (380V±15%), risking PLC stability.