The r-c combinations formed the network capacitors

In the low-frequency region of the single-stage BJT or FET amplifier, it is the R-C combinations formed by the network capacitors CC, CE, and Cs and the network re-sistive parameters that determine the cutoff frequencies. In fact, an R-C network sim-ilar to Fig. 11.8 can be established for each capacitive element and the frequency at which the output voltage drops to 0.707 of its maximum value determined. Once the cutoff frequencies due to each capacitor are determined, they can be compared to es-tablish which will determine the low-cutoff frequency for the system.

Our analysis, therefore, will begin with the series R-C combination of Fig. 11.8 and the development of a procedure that will result in a plot of the frequency response with a minimum of time and effort. At very high frequencies,

XC � �2� 1� � �fC 2�( 1� � � �0)C

voltage appears across the output terminals.