Many electronic circuits such as amplifiers are subject to instability or oscillation under certain conditions. usually these boil down to input and output terminations. There are some favorable or type b terminations which do not cause oscillation while the unfavorable terminations or type a terminations cause oscillation. The stability circle is tool that allows designers to evaluate the effect terminations have on their design using a graphical technique with the help of the Smith Chart. To learn more and understand the process, please visit and read the article in the Signal Processing Group Inc. website that explains the technique.