What does a digital waveform typically look like?

• A. Series of squares with high and low voltage states
• B. A smooth sine wave
• C. A constant voltage
• D. A random noisy signal

Answer: (A)

A digital waveform is made of distinct high and low voltage levels that are held for short periods, so when you plot it over time you see a series of flat, rectangular pulses with sharp transitions between the high and low states. That square-like shape comes from how digital signals encode information in binary, using two levels (commonly called 1 and 0) and switching between them as needed.

This is why the correct idea is a sequence of squares: each pulse represents a bit, and the timing is often governed by a clock so the transitions line up with the data. In contrast, a smooth sine wave is typical of analog signals, a constant voltage would be DC with no changing information, and a random noisy signal lacks the clean, regular transitions that convey binary data.