In digital logic, what is the primary function of an encoder device?
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AIt is used to send telegraph signals
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BIt converts an input (from one of many lines or keys) into a binary number
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CIt converts a binary number to a decimal number
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DIt can have only four keys
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ENone of the above
Answer
Correct Answer: It converts an input (from one of many lines or keys) into a binary number
Explanation
Introduction / Context:Encoders and decoders are fundamental building blocks in digital systems. Recognizing the direction of conversion—one-hot or multi-line inputs to compact binary codes—helps when designing keypads, priority circuits, and address generators.
Given Data / Assumptions:
- An encoder takes multiple mutually exclusive inputs (e.g., keys 0–9) and outputs a binary code representing the active input.
- A decoder performs the inverse operation, expanding a binary code into multiple output lines.
- We identify the correct functional description of an encoder.
Concept / Approach:A classic example is a 10-to-4 keypad encoder that maps one pressed key to a 4-bit binary output. Additional features like 'priority' handle simultaneous inputs. Telegraphy is unrelated, and an encoder’s number of inputs is not restricted to four.
Step-by-Step Solution:
1) Recall definitions: encoder vs. decoder.2) Map practical examples (keypad) to function.3) Select the option describing multi-line to binary conversion.Verification / Alternative check:Digital design texts specify n-to-log2(n) encoders and log2(n)-to-n decoders, validating the function described.
Why Other Options Are Wrong:
Telegraph signals: an unrelated communications domain.Converts binary to decimal: that is a decoder, not an encoder.Only four keys: false; encoders can have many inputs.None: incorrect since a correct description is provided.Common Pitfalls:Confusing encoders with multiplexers; while related concepts exist, their functions differ.
Final Answer:It converts an input (from one of many lines or keys) into a binary number