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 _______.

In the circuit shown, I₁ = 80 mA and I₂ b= 4mA. Transistors T₁ and T₂ are identical. Assume that the thermal voltage V_T is 26 mV at 27^oC. At 50^oC, the value of the voltage V₁₂ = V₁ - V₂ (in mV) is _______.

For the amplifier shown in the figure, the BJT parameters are V_BE = 0.7 V, $$\beta $$ = 200, and thermal voltage V_T = 25 mV. The voltage gain (V_o/V_i of the amplifier is ______.

A BJT is baised in forward active mode Assume V_BE = 0.7 V, kT/q = 25 mV and reverse saturation current I_s = 10^-13A. The transconductance of the BJT (in mA/V) is