4 views

A Darlington stage is shown in the figure is. If the transconductance of $Q_{1}$ is $g_{m 1}$ and $Q_{2}$ is $g_{m 12}$, then the overall transconductance $g_{m c}\left[\triangleq \frac{i_{c}^{c}}{v_{b c}^{c}}\right]$ is given by

1. $g_{m 1}$
2. $0.5 g_{\text {m } 11}$
3. $g_{m 2}$
4. $0.5 g_{m 2}$