Free CAAS SAR-66 M04 Electronic Fundamentals (Category B2) Practice Questions

Sample Practice Questions

Try these 10 sample questions from the CAAS SAR-66 M04 Electronic Fundamentals (Category B2) practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1What does a cathode band identify on a typical axial diode?

   1. A.The cathode terminalCorrect answer: A
   2. B.The anode terminal
   3. C.The peak current rating
   4. D.The breakdown voltage

   Explanation: The FAA states, "Dots, bands, colored bands, the letter ‘k’ or unusual shapes indicate the cathode end of the diode." The cathode terminal answers the stated component function or operating condition.

   Reference: FAA Aviation Maintenance Technician Handbook—General — 12-105, Diode Identification

2. 2What is the principal electrical purpose of a printed wiring board's conductor pattern?

   1. A.Provide mechanical cooling airflow
   2. B.Create all component resistance values
   3. C.Replace all component insulation
   4. D.Interconnect the mounted componentsCorrect answer: D

   Explanation: The source states, "an insulating base to provide interconnection for parts.". Conductive paths provide the circuit connections; the base supports and isolates those paths.

   Reference: NASA Workmanship Standard for Surface Mount Technology — 3.1

3. 3Which feature makes a servo control arrangement a closed-loop system?

   1. A.A fixed mechanical gear ratio
   2. B.Feedback from the controlled outputCorrect answer: B
   3. C.A motor connected to a power supply
   4. D.A command switch at the input

   Explanation: The FAA states, "Feedback completes a loop". The surrounding paragraph identifies this arrangement as a closed-loop system. Returning information from the controlled output closes the control loop. A gear ratio, a powered motor, or an input command switch alone does not return output information.

   Reference: FAA Aviation Maintenance Technician Handbook—Airframe — Chapter 10, printed p.10-62, Feedback or Follow-up Element, Figure 10-111 discussion

4. 4Which conversion describes the basic function of a rectifier?

   1. A.Direct current to alternating current
   2. B.Alternating current to higher-voltage AC
   3. C.Alternating current to lower-voltage AC
   4. D.Alternating current to direct currentCorrect answer: D

   Explanation: The FAA defines a rectifier as "a device that transforms AC into DC". It restricts current direction. DC-to-AC conversion is inversion; changing AC voltage without rectifying it is transformer action.

   Reference: FAA Aviation Maintenance Technician Handbook—General — 12-100, Rectifiers

5. 5What distinguishes a printed wiring assembly from a bare printed wiring board?

   1. A.It has no conductive tracks
   2. B.It must contain only one component type
   3. C.It includes parts and associated hardwareCorrect answer: C
   4. D.It contains only an unpatterned insulating sheet

   Explanation: The source states, "The PWA consists of the PWB, parts, and associated hardware and materials.". An assembly adds the components and associated materials to the board.

   Reference: NASA Workmanship Standard for Surface Mount Technology — 3.1

6. 6In a displacement follow-up system, what condition causes the feedback pickup to cancel the position error message?

   1. A.The controlled surface reaches its correct positionCorrect answer: A
   2. B.The motor reaches its maximum speed
   3. C.The supply reaches its maximum voltage
   4. D.The input command changes polarity

   Explanation: The FAA states, "cancel the error message when the surface has been moved to the correct position.". Position feedback cancels the displacement error when the commanded position has been reached.

   Reference: FAA Aviation Maintenance Technician Handbook—Airframe — 10-62, Feedback or Follow-up Element

7. 7What is the principal energy output of a forward-biased LED at its junction?

   1. A.Mechanical force
   2. B.Acoustic vibration
   3. C.LightCorrect answer: C
   4. D.Magnetic flux

   Explanation: The FAA explains that in an LED "the energy is dissipated as light." Carrier recombination releases optical energy, rather than mechanical motion, sound, or magnetic output.

   Reference: FAA Aviation Maintenance Technician Handbook—General — 12-103, Light-Emitting Diode

8. 8On a printed board, what is a land primarily used for?

   1. A.Insulating a component lead from its trace
   2. B.Connecting or attaching a componentCorrect answer: B
   3. C.Separating copper layers with a dielectric
   4. D.Connecting internal layers without a component lead

   Explanation: The source states, "used for connection or attachment, or both, of parts.". A land is a conductive attachment or connection area rather than insulation or a processing element.

   Reference: NASA Workmanship Standard for Surface Mount Technology — 3.1

9. 9A position servo progressively reduces correction as it approaches a steady target. What is the purpose of this follow-up action?

   1. A.To keep maximum motor torque indefinitely
   2. B.To eliminate the command input
   3. C.To reverse the required output position
   4. D.To prevent repeated overcorrectionCorrect answer: D

   Explanation: The FAA states, "so that continuous over correction does not take place.". Tapering the correction prevents the system from repeatedly overshooting and correcting again.

   Reference: FAA Aviation Maintenance Technician Handbook—Airframe — 10-61, Feedback or Follow-up Element

10. 10A reverse-biased photodiode receives more light, with its bias and temperature held constant. What happens to its reverse current?

    1. A.Its magnitude stays unchanged
    2. B.Its magnitude increasesCorrect answer: B
    3. C.Its magnitude decreases
    4. D.Its direction reverses

    Explanation: The FAA states, "The stronger the light, the greater the number of light-produced carriers, which in turn causes a greater magnitude of reverse-current." With bias and temperature fixed, stronger illumination increases carrier generation and therefore reverse-current magnitude.

    Reference: FAA Aviation Maintenance Technician Handbook—General — 12-104, Photodiode