The Smith chart was invented by Phillip H.

For example, if you change that parallel-matching resistor by a few percent (perhaps due to tolerance or to make it into a standard value), you can quickly see the effect on the parallel combination’s resistance. There were nomographs for everything from deciding how much paint you needed on a wall of a given size, to the resistance value needed in parallel with another known resistor to yield the final desired value.Īlthough nomographs have been made largely obsolete or quaint antique artifacts due to our cheap and easy numerical-computing power, they do have this useful aspect: they make it relatively easy to see the effect of variations around a given parameter value. The Smith chart would be classified as a “nomograph,” (also called a nomogram) which were widely used graphs for solving numerical problems in the days before calculators, computers, and software packages. It’s an essential guide to performing complex impedance transformations for transmission lines and matching circuits.

If you have done any RF work at all, you’ve seen, used, been saved by, or been mystified by this graphical tool. Whoa…how did I miss that? I’ve been a basic-level user of the Smith chart for many years, and was always fascinated by its design and history. In return, the MTT-S would make the Smith chart available to students, practitioners, and indeed people all over the world involved in microwave technology.” The news was simple: the column explained that IEEE MTT-S was buying “the rights from the Smith family of the Smith trademark belonging to Analog Instruments, along with the copyright. ” Editor’s note: Readers will need to register for a paid subscription-well worth it-Bill and I both love the excellent tech white papers That’s what happened to me recently: I was doing some online research and came across an item from October 2015, published at IEEE Microwave Magazine : “ The Smith Chart Comes Home. Even in these days, when news travels instantly and there are few secrets, it’s possible to miss an important or interesting story.

Smith chart basics pdf