What is the essential characteristic of an open circuit?

An open circuit is defined primarily by the fact that it is incomplete, preventing current from flowing through it. When a circuit is open, there is a break in the path that electrical current needs to travel, which means that electrons cannot move through the circuit. This characteristic results in no current flow, making it impossible for any connected devices to operate.

In contrast, a closed circuit, which allows continuous current flow, is the opposite of an open circuit. Options that reference resistance or high voltage are also not defining characteristics of an open circuit; while they describe aspects of other types of circuits or conditions, they do not directly pertain to the essential nature of an open circuit itself. Thus, the most accurate description of an open circuit is that it is incomplete, which inhibits current flow entirely.