Ok, so I got an Electronic homework. I have the following circuit(attachment #1) and I have to find the Voltage Gain, Input Resistance, Output Resistance, and then simulate the circuit using Pspice to verify my calculations.
Well, let me tell you that everything is going not so well to put it nicely. >_>
Ok, so let's see what I've done;
First of all I'm doing the DC analysis(attachment #2) of the circuit to find Id of the Mosfets, and Ic1 and Ic2 of the two BJT's. So, now it's given that;
Kn = 31.6 m A/V^2
Vt = 1.73 V
Lambda = 0.01 V
Beta = 200
Va = 100 V
Now, Using Voltage Divisor I calculated the Voltage of R4 which is 3.75 V. Then I used KVL on the lower left loop. Assuming that Ig = 0;
3.75 = Vgs + Id(1.8K)
Using the mosfet Id equation;
Id = 31.6m(Vgs - 1.73)^2
Now, putting those equation together I found out that;
Vgs = 1.53 V || 1.93 V, Using 1.93 V I found out that;
Id = 1.024m A
Using KVL in the middle upper loop;
(3.3k)Ie1 + 0.7 - (4k)Id = 0
Now, I get that;
Ie1 = 1.029 m A, therefore Ic1 = 1.024 m A
Now, using KVL in the lower right loop, assuming that Ib is really small(the prof gave me this tip, so yeah..)
Ie2(7k) + 0.7 - Ic1(8k) = 0
Ie2 = 1.07m A, Ic2 = 1.065 m A
Ok, that's everything. Comparing those values with the values I get from PSpice(attachment #3), they are absolutely wrong. So, can anyone point me out what am I doing wrong? Or maybe I'm doing something wrong with Pspice? ;<
I don't know. If it helps I'm using Pspice 9.1 student edition.
So please, help me. Any help is greatly appreciated,
PS: There is no given AC Voltage, but as a tip of the professor, he told us to use 1V, because he said that when we plotted the output voltage we could easily see the voltage gain.
Edwin
Well, let me tell you that everything is going not so well to put it nicely. >_>
Ok, so let's see what I've done;
First of all I'm doing the DC analysis(attachment #2) of the circuit to find Id of the Mosfets, and Ic1 and Ic2 of the two BJT's. So, now it's given that;
Kn = 31.6 m A/V^2
Vt = 1.73 V
Lambda = 0.01 V
Beta = 200
Va = 100 V
Now, Using Voltage Divisor I calculated the Voltage of R4 which is 3.75 V. Then I used KVL on the lower left loop. Assuming that Ig = 0;
3.75 = Vgs + Id(1.8K)
Using the mosfet Id equation;
Id = 31.6m(Vgs - 1.73)^2
Now, putting those equation together I found out that;
Vgs = 1.53 V || 1.93 V, Using 1.93 V I found out that;
Id = 1.024m A
Using KVL in the middle upper loop;
(3.3k)Ie1 + 0.7 - (4k)Id = 0
Now, I get that;
Ie1 = 1.029 m A, therefore Ic1 = 1.024 m A
Now, using KVL in the lower right loop, assuming that Ib is really small(the prof gave me this tip, so yeah..)
Ie2(7k) + 0.7 - Ic1(8k) = 0
Ie2 = 1.07m A, Ic2 = 1.065 m A
Ok, that's everything. Comparing those values with the values I get from PSpice(attachment #3), they are absolutely wrong. So, can anyone point me out what am I doing wrong? Or maybe I'm doing something wrong with Pspice? ;<
I don't know. If it helps I'm using Pspice 9.1 student edition.
So please, help me. Any help is greatly appreciated,
PS: There is no given AC Voltage, but as a tip of the professor, he told us to use 1V, because he said that when we plotted the output voltage we could easily see the voltage gain.
Edwin
Attachments
-
78.2 KB Views: 26
-
55.3 KB Views: 27
-
102.5 KB Views: 29
Last edited: