Hall effect sensors — what they detect: “A semiconductor using the Hall effect will detect magnetic fields.” Assess the correctness of this statement based on the Hall phenomenon.

Introduction / Context:
Hall effect sensors are ubiquitous in automotive, industrial, and consumer applications for measuring position, speed, and current. This question asks whether a semiconductor employing the Hall effect detects magnetic fields—capturing the essence of how these sensors work.

Given Data / Assumptions:

• A thin semiconductor element carries a bias current.
• A magnetic field perpendicular to the current flow is present.
• Steady-state operation with appropriate signal conditioning (e.g., amplifiers, temperature compensation).

Concept / Approach:
The Hall effect states that when a current-carrying conductor or semiconductor is placed in a magnetic field (with a component perpendicular to the current), charge carriers experience a Lorentz force, accumulating on one side and producing a transverse voltage (Hall voltage). This voltage is proportional to magnetic flux density (within the sensor’s range), enabling detection and measurement of magnetic fields. Integrated Hall sensors include amplifiers, references, and comparators to provide analog or digital outputs.

Step-by-Step Solution:

Verification / Alternative check:
Current sensors place Hall elements near busbars to measure magnetic fields from load current; rotary position sensors use magnets and Hall ICs to generate angle-dependent outputs—both practical validations of magnetic field detection.

Why Other Options Are Wrong:

• Incorrect: Directly contradicts the Hall principle.
• Valid only at cryogenic temperatures: Modern Hall ICs operate over wide industrial ranges.
• True only for ferromagnetic fields: Any magnetic field component normal to the plate is detectable; ferromagnetism is not required.
• Depends solely on carrier mobility: Mobility influences sensitivity, but detection does not depend solely on it.

Common Pitfalls:
Confusing magnetoresistive and Hall sensors; overlooking the need for proper orientation (field perpendicular to current for maximum response).

Final Answer:
Correct