Photoelectric Effect - Solar Basics
The discovery of the photoelectric effect forms the starting point for all later developments in solar technology.
The photoelectric effect, i.e. small light particles - photons - entering a metal plate and a subsequent emission of electrons was first observed in the early 19 hundreds.
The electric current running between a platinum anode and a - cathode was slightly higher in the presence of light. The reason for this is, that a negatively charged metal surface (anode) emits electrons when hit by light.
It's first real technical test photovoltaics had to pass in 1958 with the satellite Vanguard 1. Powered by solar cells the 6.4 inch in diameter Vanguard 1 send signals for seven years.