Question 10.5: Determining the Current-Amplifier Model from the Voltage-Amp...

Connect a short circuit across the output terminals and analyze the circuit to determine A_{isc} .

To find the short-circuit current gain, we connect a short circuit to the output terminals of the amplifier as shown in Figure 10.12. Then, we find that

i_i=\frac{v_i}{R_i} \text{ and }i_{osc}=\frac{A_{voc}v_i}{R_o}

The short-circuit current gain is

A_{\text{isc}}=\frac{i_{osc}}{i_i}=A_{voc}\frac{R_i}{R_o} =10^3

The resulting current-amplifier model is shown in Figure 10.13.