GROL - General Radiotelephone Operator License Digital Logic and Microcomputers Questions and Answers 1 — Questions and Answers
Question 1: In digital logic, which gate produces a HIGH output only when all of its inputs are LOW?
- AND
- OR
- NAND
- NOR (Correct answer)
Correct answer: NOR
A NOR (Not OR) gate is the logical inverse of an OR gate. An OR gate outputs HIGH if any input is HIGH. Therefore, a NOR gate will only output HIGH when all of its inputs are LOW.
Question 2: A technician is reading a memory address from a microcomputer's diagnostic screen, which displays the hexadecimal value 2F. What is the decimal equivalent of this value?
- 31
- 47 (Correct answer)
- 52
- 29
Correct answer: 47
Hexadecimal is a base-16 number system. The value 2F is calculated as (2 * 16^1) + (F * 16^0). Since F represents 15 in decimal, the calculation is (2 * 16) + (15 * 1) = 32 + 15 = 47.
Question 3: Which of the following best describes the primary characteristic of Random Access Memory (RAM) in a microcomputer system?
- It is non-volatile and stores the system's boot-up instructions.
- It is a type of permanent storage for user files and applications.
- It is volatile memory that loses its contents when power is removed. (Correct answer)
- It can only be read from and cannot be written to by the CPU.
Correct answer: It is volatile memory that loses its contents when power is removed.
RAM is volatile memory, which means its contents are lost when the system loses power. It is used by the CPU for temporary storage of data and program instructions that are actively in use. ROM (Read-Only Memory) is non-volatile and typically stores boot-up instructions.
Question 4: In a microcomputer's architecture, what is the primary function of the address bus?
- To specify the memory location or I/O port for a read or write operation. (Correct answer)
- To transfer data between the CPU and memory.
- To carry control and timing signals to all components.
- To supply electrical power to the microprocessor and peripherals.
Correct answer: To specify the memory location or I/O port for a read or write operation.
The address bus is a unidirectional set of wires used by the CPU to select a specific location in memory or a specific input/output (I/O) device that it wants to communicate with. The data bus carries the actual data, and the control bus handles timing and control signals.
Question 5: What is the fundamental purpose of a D-type flip-flop in a digital logic circuit?
- To function as a free-running oscillator.
- To amplify a weak digital signal.
- To convert a digital signal to an analog signal.
- To store a single bit of data. (Correct answer)
Correct answer: To store a single bit of data.
A flip-flop is a bistable circuit, meaning it has two stable states (representing a 1 or a 0). Its primary function is to act as a basic memory element, capable of storing one bit of information. The D-type flip-flop specifically captures and holds the value on its 'D' (data) input when triggered by a clock signal.
Question 6: An Exclusive OR (XOR) gate is a fundamental logic component. Which of the following statements correctly describes its output behavior?
- The output is HIGH if and only if all inputs are HIGH.
- The output is HIGH if an odd number of inputs are HIGH. (Correct answer)
- The output is LOW if any of the inputs are HIGH.
- The output is HIGH if any of the inputs are HIGH.
Correct answer: The output is HIGH if an odd number of inputs are HIGH.
An XOR gate produces a HIGH (1) output when its inputs are different. For a two-input gate, this means one input is HIGH and the other is LOW. This logic extends to mean the output is HIGH only when there is an odd number of HIGH inputs.
GROL - General Radiotelephone Operator License Digital Logic and Microcomputers Questions and Answers 1
In digital logic, which gate produces a HIGH output only when all of its inputs are LOW?