Analog Electronics with LabVIEW®

2.4. Transistor Output Resistance and Limiting Gain

The linear-equivalent circuit of Fig. 2.2 includes an idealization in that the output is a pure current source. In real transistors, the collector (BJT) or drain (MOSFET) current increases with increasing V_CE or V_DS. This is accounted for by including an output resistance, r_out, in the linear model, as added to the circuit in Fig. 2.5. For the BJT and MOSFET, respectively, the value of r_out is

Equation 2.9

Equation 2.10

Figure 2.5. Basic linear circuit with transistor linear model. Circuit ...