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10 February 2011
Input Resistance and Open Circuit Gain for Common Bipolar Junction Transistors
Here are some hybrid-pi models that demonstrate the small signal analysis of the common BJT configurations. These equations are universal and can be applied to any resistor/capacitor scheme. They can also be applied directly to MOSFETs. Just replace Rc=Rd, Rb=Rg, Re=Rs, and Rpi=infinity. Boom.