What is the primary cause of an open resistor fault?

An open resistor fault occurs when there is an interruption in the electrical circuit that prevents current from flowing through the resistor. This typically happens when there is an incomplete path for current flow, which can be caused by various factors such as a broken lead, a disconnected component, or degradation of the material itself. In this state, the resistor essentially behaves as if it is removed from the circuit, resulting in infinite resistance and no current flow.

The influence of an incomplete path for current flow is critical because it directly affects the function of the circuit in which the resistor is placed. Without a complete path, the resistor cannot perform its intended role, such as limiting current or dividing voltage, leading to potential circuit malfunction.

High resistance value and excessive current flow can have effects on a resistor's normal operation, but they do not specifically cause an open fault. High resistance may mean less current flows, but it doesn't result in an open circuit. Likewise, excessive current flow might lead to overheating or damage rather than creating an open fault. Visible physical damage may be an indicator of a fault but does not directly cause the open resistor condition.