Question 6.5: For the amplifier of Fig. 3-10(a), let vi = 0.25 sin(2000πt)......
For the amplifier of Fig. 3-10(a), let v_i = 0.25 \sin(2000πt) \text{V}, V_{CC} = 15 \text{V}, CC_1 = CC_2 = CC = 100 μF, R_1 = 6 kΩ, R_2 = 50 kΩ, R_C = R_L = 1 kΩ, and R_i = R_E = 100 Ω. The transistor is characterized by the model of Problem 5.4. Use SPICE methods to determine the CE hybrid parameters of (6.5) through (6.8) for this transistor at the point of operation.
Input resistance {h_{i e} \equiv \frac{\partial v_{B E}}{\partial i_{B}}\bigg|_{_{Q}} \approx \frac{\Delta v_{B E}}{\Delta i_{B}}\bigg|_{_{Q}}} (6.5)
Output admittance h_{o e} \equiv {\frac{\partial i_C}{\partial v_{C E}}}{\bigg|}_{Q} \approx {\frac{\partial\Delta i_{C}}{\Delta v_{C E}}}{\bigg|}_{Q} (6.8)
The netlist code below describes the circuit.
| EX6_5.CIR vi 1 0 SIN(0V 250mV 10kHz) Ri 1 2 100ohm CC1 2 3 1000uF CC2 4 7 1000uF R1 3 0 6kohm R2 3 6 50kohm RC 6 4 1kohm RE 5 0 100ohm RL 7 0 1kohm VCC 6 0 15V Q 4 3 5 QNPNG .MODEL QNPNG NPN(Is=10fA Ikf=150mA Isc=10fA Bf=150 + Br=3 Rb=1ohm Rc=1ohm Va=75V Cjc=10pF Cje=15pF) .TRAN 1us 0.1ms .PROBE .END |
After executing 〈Ex6_5.CIR〉, the plots of Fig. 6-8 can be generated by use of the Probe feature of PSpice. The resulting h-parameter value is indicated on each of the four plots of Fig. 6-8.
