In the common emitter amplifier in Figure 1, R1 = 500, R2 = 1k2, and CL=1 pF. Determine the quiescent collector current, Ico, needed such that the unity gain frequency, fu = 1 GHz.Show your complete solution and state all your assumptions. R2 VOUT R1 VIN Figure 1 The BJT parameters are as follows: B- 0o, VA → o, and C = 50fF. Ignore all other parasitic capacitances and use Vr = 26mV.

Figure 2 shows a typical BJT amplifier, with its parasitic capacitances displayed. The current gain of the transistor is B=150 and the voltage gain of the amplifier is Am =-125. The small signal resistances of the transistor are re =16 ohm and r0 = infinity, respectively. The values of resistors and capacitors in the figure are: R1 =80 kohm, R2 =20 Kohm, Rc = 2 Kohm, RE = 2 Kohm, Rs =50 W, RI=5 kohm, Cs=2 uF, Cc=2 uF, Ce =10 uF, Cbc =4 pF, Cbe = 10 pF, Cce =1 pF, Cwi = 4 pF, CWO = 9 pF, and Vcc = 20 V. a) Sketch a simplified circuit diagram of Figure 2 for high frequency analysis. b) Using the concept of "Miller effect capacitance", calculate the input and Output Miller effect capacitances of Figure 2, respectively. C) Determine the upper cut-off frequency of Figure 2 that is imposed by its input network only. d) Explain briefly the possible ways to increase the upper cut-off frequencv of this amplifier.

1. To use the Bipolar Junction Transistor (BJT) as a small signal amplifier it must be biased in this region: A. South Park region B. Spatial interface region C. Inverse Thevenin region D. Linear or active region