Amplifier #12. How to Find Center & Radius of Stability Circle & Plot Input/Output Stable Regions.

Amplifier (Class A, B and C) playlist.    • Amplifier #1. How to Choose Between Linear...   For access to this presentation materials, membership is required: I need the Material PPT Sent me an email to [email protected] If you need the whole playlist material, send me email and we discuss. Give me some time to response. Thanks. How to Plot the Centers & Radius of the Input & Output Stability Circles for Amp. How to Obtain the Center & Radius of Input & Output Stability Circles & Plot it. Stability circles are tools used to examine and analyze the stability of an amplifier through graphical techniques utilizing a Smith Chart. The stability circles can determine regions for ΓS and ΓL where the amplifier circuit will be conditionally stable. However, simpler tests can be used to determine unconditional stability. One such test is the K − ∆ test, which shows that a device will be unconditionally stable if Rollet’s condition, defined as along with the auxiliary condition that are simultaneously satisfied. These two conditions are necessary and sufficient for unconditional stability. If the device scattering parameters do not satisfy the K − ∆ test, the device is not unconditionally stable, and stability circles must be used to determine if there are values of ΓS and ΓL for which the device will be conditionally stable. Also recall that we must have |S11| less than 1 and |S22| less than 1 if the device is to be unconditionally stable. While the K − ∆ test is a mathematically rigorous condition for unconditional stability, it cannot be used to compare the relative stability of two or more devices because it involves constraints on two separate parameters. However, a new criterion has been proposed that combines the scattering parameters in a test involving only a single parameter, µ, defined as Thus, if µ is more than 1, the device is unconditionally stable. In addition, it can be said that larger values of µ imply greater stability. Determine the stability of this transistor by using the K − ∆ test and the µ-test and plot the stability circles on a Smith chart.