EECE 310 Homework 10, Fall 2011

American University of Beirut DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING EECE 310 – Electronics Fall 2011 – 2012 Due Wednesday January 11, 2012 at 9:00 am Homework 10 1. [20 points] Consider the BJT circuit shown in Figure 1. a) Find the minimum value of the collector voltage [10 points], such that the BJT remains in the active region. Assume  = 150. b) Find the value of RC [10 points] needed to get a collector voltage half-way between the value calculated in part (a) and VCC = +12V. Figure 1 2. [80 points] For the circuit shown in Figure 2, the BJT has  = 160 and VA = 80 V. Assume that VT = 26 mV and that all capacitors are very large. a) Find the DC values of IB [5 points], IC [5 points], and VCE [5 points]. Neglect the Early effect in DC analysis. b) Find the small-signal parameters gm [2 points], r [2 points], re [2 points], and ro [2 points]. c) Find the small-signal voltage gain of the amplifier, vo/vi [12 points]. d) Find the largest allowable signal swing (peak-to-peak) at the collector to satisfy the two conditions: BJT remains active [5 points], and vbe limited to 5 mV [5 points]. What is the corresponding allowable peak-to-peak input voltage vi [5 points]? e) Verify the results of parts (c) and (d) using PSpice [30 points]. Use the Q2N2222 part number for the BJT (available in the eval library). Figure 2