What does a continuity check primarily identify in a circuit?

A continuity check is primarily used to determine whether there is a continuous conductive path in an electrical circuit. This means it tests whether current can flow through the circuit without any interruptions. When performing a continuity check, an electrical tester measures the resistance between two points in the circuit. If the resistance is low or near zero, it indicates a good connection, while a high resistance reading suggests a break or fault in the circuit.

The focus on identifying good fuses from bad fuses is particularly relevant because fuses are designed to protect circuits by melting and breaking the connection when too much current flows. A continuity check can confirm if a fuse has blown (bad fuse) or is intact (good fuse). Therefore, the ability to differentiate between functional and non-functional fuses is a key application of continuity checks in aircraft electronics and testing procedures.