Practice Test Geeks(ABA) American Board of Audiology Practice Test
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Electrical Systems & Wiring Flashcards

7 cards from real ABA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Electrical Systems & Wiring flashcards as text

  1. What is the primary purpose of electrical grounding in an audiology test booth?

    Answer: To reduce electrical noise and protect patients from shock

    Grounding provides a low-resistance path for fault current and minimizes electrical noise that can contaminate audiological measurements.

  2. Which type of shielding is most effective at blocking low-frequency magnetic interference in audiological equipment?

    Answer: High-permeability mu-metal shielding

    Mu-metal, a high-permeability nickel-iron alloy, is the most effective material for shielding low-frequency magnetic fields.

  3. A ground loop in an audiology suite is MOST likely to produce which artifact?

    Answer: 60 Hz hum in recordings

    Ground loops create a current path between two grounded points at different potentials, inducing 60 Hz AC line-frequency hum.

  4. What is the recommended maximum skin-electrode impedance for reliable ABR recording?

    Answer: Less than 5 kΩ

    Electrode impedance below 5 kΩ (and ideally balanced between electrodes) ensures adequate signal quality and common-mode rejection for ABR.

  5. In a differential amplifier used in evoked potential recording, common-mode rejection ratio (CMRR) is important because it:

    Answer: Cancels electrical noise present on both inputs equally

    High CMRR allows the differential amplifier to reject interference signals (like 60 Hz) that appear identically on both inputs while preserving the neural signal.

  6. Which wiring configuration BEST reduces electromagnetic interference pickup in long electrode lead cables?

    Answer: Twisted-pair shielded cables

    Twisted-pair shielded cables cancel magnetically induced EMI through opposing loop areas in adjacent twists while the shield blocks electric field interference.

  7. An isolation transformer in an audiology suite primarily serves to:

    Answer: Galvanically isolate equipment from mains ground to reduce leakage current

    An isolation transformer breaks the direct conductive path from mains to equipment ground, significantly reducing potentially hazardous leakage current to patients.