Sensor switching arrangement with object size detection, esp. for glass ceramic cooking hob - comprises sensors around light source and produces output signal when one sensor detects light level above first threshold and other sensor detects light below other threshold

摘要

A light source and a number of light sensitive elements (1-4) connected to the switch are provided. The circuit produces a signal when one of the sensors, the signal sensor, receives light above a defined threshold and the other sensors, the blocking sensors, receive light below other defined thresholds. The light source is arranged within an area whose corners are defined by the positions of the sensors. The source can be placed at the geometric centre of the surface. Alternatively, the source (s) and signal sensor (1) can be placed at the geometric centre of a surface whose corners are defined by the positions of the blocking sensors (2-4). USE/ADVANTAGE - For use beneath ceramic plate of hobs for reliable, user-friendly switching of heated area according to sizes of cooking pots.