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Question 3.SP.14: For the amplifier of Fig. 3-17, CC = 100 μF, RF = 180 kΩ, RL......

For the amplifier of Fig. 3-17, C_C = 100  μF,  R_F = 180  kΩ,  R_L = 2  kΩ,  R_S = 100  kΩ,  V_{CC} = 12  \text{V}, and v_S = 4 \sin(20 × 10^3πt)  \text{V}. The transistor is described by the default npn model of Example 3.2. Use SPICE methods to (a) determine the quiescent values (I_{BQ},  I_{CQ},  V_{BEQ},  V_{CEQ}) and (b) plot the input and output currents and voltages (v_S,  i_S, v_L,  i_L).

3.17
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(a) The netlist code that follows models the circuit:

Prb3_14.CIR – CE amplifier
vS    1 0 SIN(0V 4V 10kHz)
RS   1 2 100kohm
CC1 2 3 100uF
Q  4 3 0 QNPN
RF   3 4 180kohm
RC   4 5 2kohm
VCC 5 0 12V
CC2 4 6 100uF
RL   6 0 2kohm
.MODEL QNPN NPN() ; Default transistor
.DC VCC 12V 12V 1V
.PRINT DC IB(Q) IC(Q) V(3) V(4)
.TRAN 1us 0.1ms ; Signal values
.PROBE
.END

Execute   〈Prb3_14.CIR〉   and poll the output file to find I_{BQ} = IB(Q) = 29.3  μ\text{A},  I_{CQ} = IC(Q) = 2.93  \text{mA},  V_{BEQ} = V(3) = 0.80  \text{V}, and V_{CEQ} = V(4) = 6.08  \text{V}. Since V_{CEQ} \simeq V_{CC}/2, the transistor is biased for maximum symmetrical swing.

(b) The Probe feature of PSpice is used to plot i_S,  i_L,  v_S, and v_L as displayed by Fig. 3-18. Notice the 180° phase shift between input and output quantities.

3.18

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