The current in a 21−mH inductor is given by the expressions i(t) = 0 t < 0 i(t) = 14(1 − e−t) mA t > 0 Find (a) the voltage across the inductor and (b) the expression for the energy stored in it. (a) V t < 0 v(t) = e−t μV t > 0 (b) J t < 0 w(t) = (1 − e−t)2 μJ t > 0
Common Base Amplifier: The figure below shows a common base amplifier using an NPN BJT which has a common emitter current gain of β = 100, and a base-emitter voltage of VBE = 0.7 V. Ignore the Early effect, i. e. take VA = ∞. The resistor values are RC = 5.7 kΩ, RE = 1 kΩ, RB1 = 47 kΩ, and RB2 = 8.2 kΩ. The supply voltage is VCC = 12 V. The BJT's collector current is IC≅1 mA. a) Calculate the unloaded voltage gain, Avo, input resistance Rin and output resistance Rout of the amplifier. b) What are the loaded voltage gain, Av, and overall gain Gv if Rsig = 50 Ω and RL = 10 kΩ? c) What are the loaded voltage gain, Av, and overall gain Gv if Rsig = 1 kΩ and RL = 1 kΩ? Figure 2. Common base amplifier for question 2.