Which waveform has sharp transitions between two voltage levels?

• A. Sine Waves
• B. Square Waves
• C. Triangular Waves
• D. Sawtooth Waves

Answer: (B)

Abrupt switching between two fixed voltage levels is the defining trait being tested. A square wave sits at a high level for a time, then flips instantly to a low level, and stays there until the next transition. Those vertical, almost instantaneous edges are what create the two-level behavior with sharp transitions.

Sine waves never jump; they curve smoothly between peaks. Triangular waves do switch direction with sharp corners, but they still move gradually between the two extremes rather than snapping instantly from one level to the other. Sawtooth waves change abruptly too, but they don’t linger at just two discrete levels—the waveform continuously sweeps through many voltages across most of the cycle.

So the waveform that truly embodies two levels with sudden transitions is the square wave.