But not only on roofs you find applications of the photovoltaic effect. Also in calculators, garden lights, etc. you find solar cells, which supply them with electricity. Even light sensors, so-called photodiodes, take advantage of the the photovoltaic effect.
To understand how this works, you need to have a look at the photovoltaic effect in more detail. On the following pages you experiment with solar cells and photodiodes, and you understand the basic characteristics of the effect.
To get started you need to do a few preparations.