Fault diagnosis with a current tracer: If a gate's output has an internal short, what will the current tracer reveal about the faulty point on the board?

Introduction / Context:
In digital troubleshooting, a current tracer is a handheld probe that senses the magnetic field around a conductor to show the direction and relative magnitude of current flow. When a logic output suffers an internal short within an IC, recognizing what the tracer can identify is crucial for efficient fault isolation.

Given Data / Assumptions:

• One gate output is internally shorted inside its IC package.
• Board traces connect that output node to loads or other inputs.
• The circuit is powered so fault current flows along the net to the IC pin.

Concept / Approach:
A current tracer helps follow the path of abnormal current on a powered board. By tracing along the copper from the supply through series elements to the suspicious node, the technician can locate the component pin where current terminates into the fault. If the short is inside the gate, the current flow will “point” into that IC pin, uniquely identifying the defective gate rather than a downstream load node.

Step-by-Step Solution:

Verification / Alternative check:
Lift the suspect pin or remove the IC; if the abnormal current ceases, this confirms the gate as defective. Thermal imaging or freeze spray may corroborate (hot IC).

Why Other Options Are Wrong:

Common Pitfalls:
Using the tracer on unpowered boards; misinterpreting bidirectional bus currents; ignoring current division across parallel paths; skipping current limiting during fault-finding.

Final Answer:
identify the defective gate