392

CIRCUIT ANALYSIS USING SPICE AND PSPICE

[CHAP. 15

15.11 Find the The´venin equivalent of Fig. 15-32 seen at the terminal AB:

Fig. 15-32 From dc analysis we ﬁnd the open-circuit voltage at AB. We also use .TF to ﬁnd the output resistance at AB. The source ﬁle and the output ﬁles are Solution to Fig. R1 0 R2 0 R3 1 R4 2 R5 4 Vs1 2 Vs2 3 Is 0 .TF V(5) .END

15-32 and The´venin equivalent at terminal AB 1 2 3 6 3 1 3 5 5 7 1 DC 3 4 DC 4 5 DC 1 Vs1

The output ﬁle contains the following results: NODE VOLTAGE (1) 1.2453 (5) 5.2642

NODE VOLTAGE (2) 4.2453

NODE VOLTAGE (3) 2.2642

NODE VOLTAGE (4) 1:7358

VOLTAGE SOURCE CURRENTS NAME CURRENT Vs1 3:962E  01 Vs2 1:000E þ 00 TOTAL POWER DISSIPATION

5:19E þ 00

WATTS

Vð5Þ=Vs1 ¼ 1:132E  01 INPUT RESISTANCE AT Vs1 ¼ 5:889E þ 00 OUTPUT RESISTANCE AT Vð5Þ ¼ 8:925E þ 00 The The´venin equivalent is VTh ¼ V5 ¼ 5:2642 V, RTh ¼ 8:925 .

15.12 Plot the frequency response VAB =Vac of the open-loop ampliﬁer circuit of Fig. 15-33(a). The following source ﬁle chooses 500 points within the frequency varying from 100 Hz to 10 Mhz. Open loop frequency response of ampliﬁer, Fig. 15-33 Rs 1 2 10 k Rin 0 2 10 E5 Cin 0 2 short 1 Rout 3 4 10 k R1 4 0 10 E9 Eout 3 0 0 2 1 E5 Vac 1 0 AC 10 u 0 .MODEL short CAP(C ¼ 1Þ

Mahmood_Nahvi_eBook_Schaum_s_Outlines_Theory_An
Mahmood_Nahvi_eBook_Schaum_s_Outlines_Theory_An