Finding an open PCB track: Which handheld troubleshooting tool most effectively helps trace where current stops along a printed conductor without cutting traces?

Introduction / Context:
Open-circuit faults on printed circuit boards (PCBs) can be difficult to locate visually, especially in fine-pitch or multilayer designs. Field technicians rely on tools that localize where current flow ceases along a conductor to pinpoint the break without desoldering or cutting copper.

Given Data / Assumptions:

• The board can be powered safely to allow current flow for tracing.
• Goal: identify the exact location where current no longer flows along a net.
• Access may be limited due to solder mask or internal layers.
• Non-invasive methods are preferred to avoid further damage.

Concept / Approach:
A current tracer senses the magnetic field generated by current in a conductor and provides a visual or audible indication of current presence. By moving the probe along the trace, you find the point where the indication stops—right at or just before the open. A multimeter can detect opens at two points but not easily localize mid-trace faults without probing many vias. Logic probes indicate logic levels, not current flow. Oscilloscopes can show signal activity but are less convenient for continuous current path localization.

Step-by-Step Solution:

Verification / Alternative check:
After identifying the suspected break, use a DMM in continuity mode across the localized region to confirm the open, and then repair via microjumper, reflow, or trace patch as appropriate.

Why Other Options Are Wrong:

Common Pitfalls:
Using too little current to be detected; tracing on powered boards without observing safety and ESD precautions; misinterpreting results on parallel paths where current may bypass a section.

Final Answer:
current tracer