Practice Test Geeks(AET) Aircraft Electronics Technician Practice Test
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Digital Electronics and Microprocessors Flashcards

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

Read the first 7 Digital Electronics and Microprocessors flashcards as text

  1. In a microcontroller used in aircraft fuel management, what is the purpose of a watchdog timer?

    Answer: To reset the processor if software fails to service the timer within a set interval

    A watchdog timer automatically resets the microcontroller if the main program becomes stuck and fails to periodically 'kick' (service) the timer.

  2. The hexadecimal number 0xAF converted to decimal is:

    Answer: 175

    0xAF = (10 × 16) + 15 = 160 + 15 = 175 in decimal.

  3. What type of memory is typically used to store the boot firmware in an avionics Line Replaceable Unit (LRU)?

    Answer: Flash (EEPROM)

    Flash (EEPROM) is non-volatile and retains firmware without power, making it standard for avionics LRU boot code storage.

  4. In a tri-state bus architecture used in avionics backplanes, what is the purpose of the high-impedance (Hi-Z) state?

    Answer: To allow a device to disconnect electrically from the bus without causing conflicts

    The Hi-Z state effectively disconnects a device's output from the shared bus, preventing bus contention when multiple devices share the same lines.

  5. A shift register in a serial-to-parallel converter for avionics data acquisition receives bits MSB first. After clocking in the 8-bit word 10110100, what is bit 0 (LSB) of the parallel output?

    Answer: 0

    The word 10110100 binary has its LSB (bit 0) as 0, which is the last bit shifted in when transmitting MSB first.

  6. Which type of analog-to-digital converter (ADC) is preferred in avionics for highest accuracy at lower sample rates, such as pressure sensor digitization?

    Answer: Delta-sigma ADC

    Delta-sigma ADCs achieve very high resolution through oversampling and noise shaping, making them ideal for slow but precise measurements like pressure.

  7. In ARINC 629 multi-transmitter data bus used on the Boeing 777, how is bus access controlled?

    Answer: Each terminal uses a decentralized CSMA/CA protocol with periodic and aperiodic transmission

    ARINC 629 uses a decentralized protocol where each terminal autonomously manages periodic and aperiodic data transmission without a central bus controller.