CET Digital Logic & Microprocessors 4

Question 1

A euthanasia chamber's microprocessor checks a door-sensor pin and reads logic level 0 (LOW). The system is designed with active-LOW logic for safety. What does this reading indicate?

Accepted Answer

The door is closed and the safety condition is met

Answer

In active-LOW logic, a LOW (0) signal represents the active or asserted condition, so a LOW door sensor means the door is closed and the safety interlock is satisfied.

Question 2

A euthanasia system uses a watchdog timer. If the microprocessor program freezes or enters an infinite loop, what does the watchdog timer do?

Accepted Answer

Resets the microprocessor to restore normal operation

Answer

A watchdog timer resets the microprocessor if the software fails to periodically 'kick' or reset the timer, recovering the system from software hangs.

Question 3

Which logic family is most commonly used in modern euthanasia equipment microcontrollers due to its low power consumption and wide noise immunity?

Accepted Answer

CMOS (Complementary Metal-Oxide-Semiconductor)

Answer

CMOS logic dominates modern microcontrollers because it draws minimal current in static states, provides excellent noise immunity, and operates over a wide voltage range.

Question 4

In a euthanasia equipment control program stored in memory, machine code instructions are executed by the CPU in a repeating sequence. What is the correct order of this sequence?

Accepted Answer

Fetch → Decode → Execute

Answer

The instruction cycle always follows Fetch (retrieve instruction from memory), Decode (interpret the instruction), Execute (perform the operation).

Question 5

A euthanasia system's ADC reads a pressure sensor outputting 0–5V and converts it to a 10-bit digital value. What is the voltage resolution of each digital step?

Accepted Answer

~4.88 mV

Answer

A 10-bit ADC over a 5V range has 2^10 = 1024 steps; 5V ÷ 1024 ≈ 4.88 mV per step.

(CET) Certified Euthanasia Technician Practice Test

(CET) Certified Euthanasia Technician Practice Test

CET Digital Logic & Microprocessors 4