Which NOT listed as a current shape?

Which NOT listed as a current shape?

• A. Cosine
• B. Sine
• C. Triangular
• D. Spike

Answer: (A)

The main idea here is how current shapes are described in electrotherapy. Clinicians distinguish waveforms by how the current’s amplitude changes over time, and several distinct shapes are commonly used: a smooth, periodic waveform (sine), a ramped-up and down form (triangular), and short, sharp bursts (spike). A cosine wave isn’t treated as a separate current shape in this context because it is mathematically the same as a sine wave, just shifted in time. In other words, a cosine is essentially a sine with a phase shift, so it isn’t listed as a distinct shape for practical purposes. That’s why cosine is not listed as a current shape. The other options—sine, triangular, and spike—are recognized, separate shapes that describe how the current rises and falls over time.

The main idea here is how current shapes are described in electrotherapy. Clinicians distinguish waveforms by how the current’s amplitude changes over time, and several distinct shapes are commonly used: a smooth, periodic waveform (sine), a ramped-up and down form (triangular), and short, sharp bursts (spike). A cosine wave isn’t treated as a separate current shape in this context because it is mathematically the same as a sine wave, just shifted in time. In other words, a cosine is essentially a sine with a phase shift, so it isn’t listed as a distinct shape for practical purposes.

That’s why cosine is not listed as a current shape. The other options—sine, triangular, and spike—are recognized, separate shapes that describe how the current rises and falls over time.