Many of the everyday mechanisms we take for granted, such as automatic lighting of street lamps as daylight fades, how the elevator doors remain open when there is someone in the way, the device that regulates printer toner, and breathalyser tests- all of these use photoelectric cells that are based on Einstein’s theories.
Photoelectric cells, originally used to detect light, used a vacuum tube containing a cathode (to emit electrons) and an anode (to gather the resulting current). Modern versions of these “phototubes” have advanced to semiconductor-based photodiodes. These find applications in solar cells and fibre optics telecommunications.
Photomultiplier tubes are a variation of the phototube. Devices like solar panels that turn light into electricity are possible because of the photoelectric effect.
Picture Credit : Google
