With a series connection, two electrical equipment, e.g. a ceiling light and a fan, can be switched on and off from one switching point. For this purpose, two off switches or changeover switches can be installed in a housing (a so-called double rocker) that have a common connection. However, this circuit is no longer common in building electrical installations today, it dates back to a time when there were only rotary switches. In circuit technology, the term series connection describes a series connection of components.
Image: Symbol serial connection - bauwion
Source: bauwion
