Free UK CAA Part-66 Module 4 Electronic Fundamentals (B1.1) Practice Questions

Sample Practice Questions

Try these 10 sample questions from the UK CAA Part-66 Module 4 Electronic Fundamentals (B1.1) practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1What does a band marking normally identify on a semiconductor diode?

   1. A.The anode terminal
   2. B.The junction material
   3. C.The rated current
   4. D.The cathode terminalCorrect answer: D

   Explanation: The FAA handbook states: "Dots, bands, colored bands, the letter ‘k’ or unusual shapes indicate the cathode end of the diode." The marking identifies polarity, not current rating or semiconductor composition.

   Reference: FAA Aviation Maintenance Technician Handbook—General — Diode Identification

2. 2What are the two basic roles of a printed circuit board in an electronic assembly?

   1. A.Electrical interconnection and mechanical component supportCorrect answer: A
   2. B.Mechanical component support and automatic data storage
   3. C.Electrical interconnection and automatic current amplification
   4. D.Electrical insulation and automatic voltage generation

   Explanation: Altium states that a PCB "uses copper conductors to create electrical connections between components. PCBs also provide mechanical support for electronic components". These are passive board roles; active signal processing and memory functions require appropriate components.

   Reference: Altium — What Is a PCB? — What is a Printed Circuit Board?

3. 3Which feature identifies a closed-loop system used for motor control?

   1. A.It uses measured motor state as feedbackCorrect answer: A
   2. B.It uses only a preset mechanical stop
   3. C.It issues commands without measuring motor state
   4. D.It fixes motor speed solely through supply frequency

   Explanation: The source states: "Whenever motor feedback is processed, it is a closed-loop system." Processing actual motor feedback closes the loop. Preset commands, supply frequency and mechanical stops alone do not establish feedback.

   Reference: Analog Devices — Closed-Loop Motor Control — What Makes a Closed-Loop System in Motor Control?

4. 4A reverse-biased photodiode receives increasing light intensity. What normally happens to its reverse current?

   1. A.It reverses its direction of flow
   2. B.It increases as illumination risesCorrect answer: B
   3. C.It decreases as illumination rises
   4. D.It remains fixed by the package

   Explanation: The FAA handbook states: "The stronger the light, the greater the number of light-produced carriers, which in turn causes a greater magnitude of reverse-current." This light-dependent current is the sensing property; increasing illumination does not reverse the current direction.

   Reference: FAA Aviation Maintenance Technician Handbook—General — Photodiode

5. 5What is the electrical role of the dielectric material between PCB copper layers?

   1. A.To replace the solder attaching surface components
   2. B.To amplify the signal carried by each copper track
   3. C.To provide a direct conductive path between layers
   4. D.To provide insulation between conducting layersCorrect answer: D

   Explanation: The source states: "The layer stack-up is built with alternating layers of conductive and insulating material" The dielectric separates conductors electrically; it is not the intended current path, amplifier or component attachment.

   Reference: Altium — What Is a PCB? — Structure and Applications of PCBs

6. 6In a correctly connected position servo, what direction should the motor move in response to a position error?

   1. A.A direction fixed independently of the error
   2. B.A direction selected only by supply frequency
   3. C.A direction that increases the position error
   4. D.A direction that reduces the position errorCorrect answer: D

   Explanation: The source states: "The motor, which is geared back to the CT rotor shaft, will turn to oppose the voltage causing its motion." Corrective motion opposes the error signal. Motion that enlarges or ignores the error is not normal negative-feedback action.

   Reference: Moog — Synchro Application Guide — Control Transformer, pp.218–219

7. 7Which component emits light when operated with forward current?

   1. A.A varistor device
   2. B.A photodiode sensor
   3. C.A rectifier diode
   4. D.A light-emitting diodeCorrect answer: D

   Explanation: The FAA handbook states: "However, in the light-emitting diode (LED), the energy is dissipated as light." An LED converts electrical energy to light. A photodiode senses light; rectifiers control current direction and varistors limit surges.

   Reference: FAA Aviation Maintenance Technician Handbook—General — Light-Emitting Diode (LED)

8. 8Why is copper commonly used for PCB conductors?

   1. A.It provides high resistance along each intended signal path
   2. B.It provides low resistance to electrical signal conductionCorrect answer: B
   3. C.It provides the insulation between adjacent conductor layers
   4. D.It stores the signal as magnetization within each trace

   Explanation: The source states: "A metal used in the fabrication of PCBs for its low resistance to the conduction of electrical signals." Copper carries signals with low resistance. The other choices confuse conduction with insulation or storage.

   Reference: Altium — Guide to PCB Terminology — Layout PCB Design Glossary — Copper

9. 9In a position follow-up system, what is the commanded input intended to determine?

   1. A.The steady angular speed of the output shaft
   2. B.The torque exerted by the output mechanism
   3. C.The current commanded through the motor windings
   4. D.The position reached by the output mechanismCorrect answer: D

   Explanation: The source states: "Ideally, the servo loop tries to drive the motor output position, as measured by the feedback device, to be as close as possible to the commanded position." A position follow-up command sets demanded position; speed, torque and current demands are different controlled quantities.

   Reference: Kollmorgen — Which Position Feedback Is Right for Your Application? — How is position feedback used? — Servo control loop

10. 10What is the basic purpose of a rectifier in an electrical circuit?

    1. A.To change alternating current into direct currentCorrect answer: A
    2. B.To change direct current into alternating current
    3. C.To store charge until a switching event occurs
    4. D.To vary inductance with an applied magnetic field

    Explanation: The FAA handbook states: "A rectifier is a device that transforms AC into DC by limiting or regulating the direction of current flow." Rectification uses directional conduction. Inversion, charge storage and magnetic control describe different functions.

    Reference: FAA Aviation Maintenance Technician Handbook—General — Rectifiers