Eli5 How does a smartphone turn on and off the flash light if there is not “switch”?


I am a mechanical engineer so I dont really know de details of how electronics turn switches on or off without mechanical help

In: Technology

there is a switch, it’s just electronic. Look into transistors, they act as electronic switches.

They’re made of silicon with some extra stuff mixed in. That extra stuff changes the electrical properties of silicon. A layer of silicon that normally doesn’t conduct very well is sandwiched between two layers that conduct it extra well (the reverse also works). When you apply a voltage to the center layer, the properties change and now it’s able to conduct electricity. You may have heard silicon referred to as a semi-conductor. This is why, it can act as either a conductor or an insulator depending on the circumstance.

since you understand switches and relays, the best way I can explain is that the processor is filled with tiny switches and when the programming dictates that the LED needs to be lit, a small voltage signal is sent to a solid state relay that connects the LED driver circuit to the battery to power the LED led flash