Study Compendium (2025–2026):
Actual Exam-Style Questions with
Verified Correct Answers, Detailed
Clinical Rationales, and Core
Competency Review Covering
Instrumentation, Waveform
Morphology, Seizure Identification,
and Patient Safety Protocols
SECTION 1: BASIC ELECTRONICS & OHM'S LAW (Questions 1–15)
1. What is closely related to the measurement of voltage in relation to
current and resistance?
Answer: Ohm's Law (E = I × R)
Rationale: Ohm's Law defines the relationship between voltage (E),
current (I), and resistance (R). The three formulas are E = I×R, I = E/R,
and R = E/I.
2. The basic unit for measuring current flow is:
, Answer: Ampere
Rationale: The ampere (A) is the SI unit of electric current. Coulomb
measures charge, volt measures potential difference, and atomic
weight is unrelated.
3. The basic unit of resistance is:
Answer: Ohm
Rationale: The ohm (Ω) is the SI unit of electrical resistance. Coulomb
measures charge, ampere measures current, and volt measures
voltage.
4. Which of the following is NOT a valid expression of Ohm's Law?
Answer: R = EI (or R = VI)
Rationale: The correct expressions are E = IR, I = E/R, and R = E/I. R =
EI is incorrect because resistance equals voltage divided by current,
not multiplied.
5. Which of the following is NOT a unit for measuring alternating
frequencies?
Answer: Volts
Rationale: Frequency is measured in cycles per second, hertz (Hz), or
kilocycles. Volts measure electrical potential, not frequency.
6. What is frequency influenced by and what is it measured in?
Answer: Sampled by sampling rate; measured in Hz
Rationale: Frequency is determined by how often a waveform repeats
per second. The sampling rate must be sufficient to accurately capture
the frequency, and the unit of measurement is hertz (Hz).
7. Time constant is defined as the time required to:
, Answer: For the deflection to fall (decay) to 67% of the peak
deflection
Rationale: The time constant is the time required for a voltage to
decay to 37% (or fall by 63%) of its original value. Some sources state
67% depending on the reference point.
8. A long time constant corresponds to which low-frequency filter
setting?
Answer: LFF 0.1 Hz
Rationale: A longer time constant allows lower frequencies to pass
through. A 0.1 Hz low-frequency filter (LFF) produces a longer time
constant compared to higher LFF settings.
9. The EEG amplifier is designed so that when input 1 is more negative
than input 2, the deflection will be:
Answer: Upward
Rationale: In differential amplifiers, the polarity convention dictates
that when input 1 (G1) is more negative than input 2 (G2), an upward
deflection is produced.
10. The amount by which the differential amplifier increases the
magnitude of the input signal is:
Answer: Sensitivity
Rationale: Sensitivity refers to the amplifier's gain—how much it
amplifies the input signal. It is expressed in microvolts per millimeter
(μV/mm).
11. Common Mode Rejection is defined as:
, Answer: The characteristic of an amplifier that rejects external
interference
Rationale: Common mode rejection ratio (CMRR) measures an
amplifier's ability to reject signals that are common to both inputs
(like 60 Hz interference) while amplifying the differential signal.
12. What is the result of failure to sample the analog signal at a
sampling rate at least twice as fast as the fastest wave to be resolved?
Answer: Aliasing
Rationale: The Nyquist theorem states that sampling must occur at
least twice the highest frequency to avoid aliasing, where high-
frequency signals are misrepresented as lower frequencies.
13. A low bit capacity results in waveform tips squaring off. What is
this called?
Answer: Clipping
Rationale: Clipping occurs when the analog-to-digital converter's bit
capacity is insufficient to represent the full amplitude range of the
signal, causing the peaks to appear flattened or "squared off".
14. During recording of cerebral activity, the calibration input voltage
is changed from 50 μV to 100 μV. What will the result be?
Answer: No effect on the activity being recorded
Rationale: Changing the calibration voltage affects the calibration
signal only; it does not alter the patient's cerebral activity being
recorded.
15. A high frequency setting of 35 Hz would attenuate 50 Hz muscle
activity by approximately what percentage?