What term is used for the peak value of a sine wave?

What term is used for the peak value of a sine wave?

• A. Average value
• B. Peak-to-peak value
• C. Peak value
• D. RMS value

Answer: (C)

The peak value is the maximum instantaneous value of a sine wave. For a sine wave written as Vm sin(ωt), Vm is the peak value (also called the amplitude). It tells you how large the waveform gets from zero in either direction. This is different from the RMS value, which is the effective value related to power; for a sine wave the RMS value is Vm divided by the square root of two. It’s also different from the peak-to-peak value, which is the total distance from the highest point to the lowest point and equals 2Vm. The average value over a full cycle of a pure sine wave is zero because the positive and negative halves cancel each other out, so average isn’t used to describe the height of the waveform. If you know the peak value, you can find the others easily: RMS is Vm/√2, and peak-to-peak is 2Vm. For example, a peak value of 120 V gives about 84.8 V RMS and a 240 V peak-to-peak swing.

The peak value is the maximum instantaneous value of a sine wave. For a sine wave written as Vm sin(ωt), Vm is the peak value (also called the amplitude). It tells you how large the waveform gets from zero in either direction.

This is different from the RMS value, which is the effective value related to power; for a sine wave the RMS value is Vm divided by the square root of two. It’s also different from the peak-to-peak value, which is the total distance from the highest point to the lowest point and equals 2Vm. The average value over a full cycle of a pure sine wave is zero because the positive and negative halves cancel each other out, so average isn’t used to describe the height of the waveform.

If you know the peak value, you can find the others easily: RMS is Vm/√2, and peak-to-peak is 2Vm. For example, a peak value of 120 V gives about 84.8 V RMS and a 240 V peak-to-peak swing.