In the figure shown, the npn transistor acts as a switch.

For the input v_in(t)as shown in the figure, the transistor switches between the cut-off and saturation regions of operation, when T is large. Assume collector-to-emitter voltage saturation V_CE(sat) = 0.2V and base-to-emitter voltage V_BE = 0.7V. The minimum value of the common-base current gain$$\left( \alpha \right)$$ of the transistor for the switching should be _________.

For the DC analysis of the Common-Emitter amplifier shown, neglect the base current and assume that the emitter and collector current are equal. Given that V_T = 25mV, V_BE = 0.7V, and the BJT output r₀ is practically infinite. Under these conditions the midband voltage gain magnitude, a_v = $$\left| {{v_0}/{v_i}} \right|\,\,\,V/V,$$ is _____

In the circuit shown, transistors Q₁ and Q₂ are biased at a collector current of 2.6 mA. Assuming that transistor current gains are sufficiently large to assume collector current equal to emitter current and thermal voltage of 26m V, the magnitude of voltage gain V_o/V_s in the mid-band frequency range is _____________ (up to second decimal place).

In the ac equivalent circuit shown, the two BJTs are biased in active region and have identical parameters with β >> 1. The open circuit small signal voltage gain is approximately _______.