Optical-based smoke alarms use light instead. They are slightly better at detecting the large smoke particles created by slow, smouldering fires. When such particles enter a chamber in the device, they scatter light from a small light source, which is then picked up by a photoelectric sensor.
If you’re interested in more details, check out the Component Book or watch “What is a Component?”.
，这一点在同城约会中也有详细论述
Responding to the offer, BMA resident doctors committee chairman Dr Jack Fletcher said "it does nothing to restore pay for doctors, which remains well within the government's power".
▲ 乔布斯与辛普森，中间的是乔布斯的女儿丽萨 · 布伦南-乔布斯