SPI Formulas (Relationships)

Physicists call them equations.  You may call them formulas.

We know them as relationships.  Love them or hate them, they are a necessary part of understanding Sonography Principles and Instrumentation.

While it is unlikely that you will need to use these equations to do calculations,  the value of knowing these equations is that they show you the relationships between the variables.

For example,  from the wave equation on this page, you can see that wavelength is inversely proportional to frequency, and from the range equation that reflector distance is directly proportional to the go-return time. 

Here is a comprehensive list of these relationships.  Sometimes it's nice just to have everything in one place :)