56 views

Consider the common-collector amplifier in the figure (bias circuitry ensures that the transistor operates in forward active region, but has been omitted for simplicity). Let $I_C$ be the collector current, $V_{BE}$ be the base-emitter voltage and $V_T$ be the thermal voltage. Also, $g_m$ and $r_0$ are the small-signal transconductance and output resistance of the transistor, respectively. Which one of the following conditions ensures a nearly constant small signal voltage gain for a wide range of values of $R_E$?

1. $g_mR_E <<1$
2. $I_CR_E>>V_T$
3. $g_mr_o>>1$
4. $V_{BE}>>V_T$