Question 3 (4 Marks) Q.A. 3 -Statement: DC biasing of a CE amplifier circuit is as in Fig.3. Assu...

Question 3 (4 Marks) Q.A. 3 -Statement: DC biasing of a CE amplifier circuit is as in Fig.3. Assume the parameters, Vcc, Veq and RBI as: 9 volt, 1.5 volt and 180k respectively. Further, B = 125 for all the transistors involved; load resistance Rı= 1200 ohm, collector resistance, Rc 1800 ohm and source resistance, Rs =2000 ohm. The amplifier is excited by a source, vs(t) = A * sin(21ft) with A = 100 mV peak and f = 3000 Hz; further, the coupling capacitors can be assumed to be of zero reactance at the working frequency. Required Solutions: Determine the following: Input resistance Rin (as seen by the ac signal source at the input); value of biasing resistance Rb2 indicated for BJT marked as Te. (Note Te emulates an equivalent emitter resistance; Req equal to: (VeQ/IE): AC load- current (rms value of il) through R, and (Vcq; Ico; IBQ; IgQ). Fig. 3 +V TO RC RBI Сс Cc2 in VBQ R +V R = ? B2 RL + S il

Multiple-choice answers 1. (Rin = 37k; RB1 = 180k; RB2 = 1.074k), (VcQ = 5.25 volt; Ico = 0.529 mA; IBQ = 34 microA; leq = 0.5296 mA); Req - 2.83 ohm; i;= 14.98 mA rms) 2. (R.in = 27k; RB1 = 280k; RB2 - 2.054k), (VcQ = 7.25 volt; Ice = 0.629 mA; IBQ = 45 microA; Ieq = 660.6 mA); Req - 12.80 ohm; i = 4.93 mA rms) 3. (Rin = 59k; Rp1 = 280k; RB2 – 3.075k), (VcQ = 3.25 volt; Ico = 129.5 mA; IBQ 31 microA; leg = 429.6 mA); Req -4.83 ohm; i = 24.98 mA rms) 4. (Rin = 33k; RB1 = 120k; RB23.064k), (VcQ = 2.25 volt; Ice = 229.5 mA; IBQ = 30 microA; Iso = 229.6 mA); Req -1.83 ohm; i = 41.98 mA rms) 5. (Rin = 33k; RB1 = 180k; RB2 - 2.074k), (VcQ = 5.50 volt; Ice = 689.5 mA; Iso = 15 microA; IEQ = 159.6 mA); Req - 4.83 ohm; i = 11.98 mA rms)