PAS

The pedal assist sensor, commonly known as the PAS sensor, is a critical component of nearly every electric bicycle. Its primary function is to act as the "on switch" and control interface for the motor when the rider is pedaling.

In short, the PAS sensor detects when and how the rider is pedaling and signals the e-bike's controller to provide electric assistance. The motor assistance only engages when the sensor detects pedaling motion, creating a more natural cycling experience compared to a throttle-only system.