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How to Calculate the Effectiveness of a Square Wave

In electronics, alternating current (AC) waveforms are used in both everyday technologies and in scientific experiments. The most common AC waveform is a simple sinusoid and looks very much like a sine or cosine wave. This is the general form that AC electricity within households takes. Sometime it is more beneficial to use a square wave, so that only two discrete values are possible. The effectiveness (also known as root mean square) of a square wave can be calculated using a simple formula.

Things You'll Need

Calculator

Instructions

- 1
  Find the peak voltage of the square wave. The peak voltage of a square wave is the voltage value where the wave is completely horizontal. Write down the value of peak voltage in units of Volts. For example, the peak voltage may be 5 Volts.
- 2
  Write down the equation for effectiveness of a square wave:
  
  Veffective=SQRT((2/3.14)(Vpeak^2)(3.14/2))
  
  Here SQRT means square root the contents of the brackets, and Vpeak is the peak voltage. The first and final terms within the square root cancel giving:
  
  Veffective=SQRT(Vpeak^2)
- 3
  Plug the peak voltage into the equation. Following the example:
  
  Veffective=SQRT(5^2)=SQRT(25)=5 V
  
  Hence for a square wave, the effectiveness is equal to the peak voltage.

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