Decoder vs. encoder: A digital circuit that converts coded information into a familiar, human-readable, or non-coded form (such as driving a display) is called an ________.

Introduction / Context:
Two fundamental blocks in digital systems are encoders and decoders. Although their names sound similar, they perform inverse operations. Correctly identifying which circuit expands a coded input into a familiar or non-coded output (such as segment lines for displays) is crucial when interfacing with human-readable devices.

Given Data / Assumptions:

• “Coded information” means a compact representation (e.g., BCD or binary).
• “Familiar/non-coded form” often refers to line patterns like seven-segment outputs.
• We are considering basic combinational blocks (no memory).

Concept / Approach:
An encoder compresses many input lines into a smaller coded output (e.g., 8-to-3). A decoder expands a coded input into many outputs or a display-friendly format (e.g., 3-to-8 decoder, BCD-to-7-segment driver). Therefore, a circuit that takes coded input and produces a human-recognizable output is a decoder.

Step-by-Step Solution:

Verification / Alternative check:
Typical ICs like 74HC138 (3-to-8 decoder) or 74HC4511 (BCD-to-7-segment decoder/driver) demonstrate taking a compact code and driving many output lines for display or selection, confirming the function is decoding.

Why Other Options Are Wrong:

• Encoder: Performs the reverse (many inputs to fewer coded outputs).
• Buffer, multiplexer, latch: Serve other roles (drive strength, selection among inputs, or storage) rather than code expansion for display.

Common Pitfalls:
Confusing the “direction” of information (compression vs. expansion); assuming any display driver is an encoder when it is typically a decoder/driver.

Final Answer:
decoder