Help me analyse two circuits

[mohazaga]

hi , can you help me to analyze the following circuits ( determint the values of v1,v2,v3,v4&v5 ) also if any body has the solution manual of Microelectronics circuit by Sedra
Thanks
waiting

 

[tyassin]

Re: circuit analysis

Hej

You can get the solution manual in the e-book download section.

If you start with the first circuit.
You don't know the current through the transistors or the voltages at the nodes(V1 and V2). But you can write two equations which can solve this. Starting at the bottom transistor

1: I=½×Kn×(Vgs-Vt)² This is the formula to calculate the current in an FET with a given Vgs.
2: V2=-5V+I×1KΩ

Also remember that Vgs can be written as follows:

3: Vgs=Vg-Vg. In your case Vg=0V and Vg=V2 so
Vgs=-V2=5V-I×1KΩ

As you now see you have two equations with two unknowns.

Regards

 

[BrunoK]

Re: circuit analysis

Here is the link:

 

[mohazaga]

Re: circuit analysis

Thanks ,
can we apply same procedure for the second circuit ?

 

[tyassin]

Re: circuit analysis

Hi

In the second circuit, you can use the same approach.

First equation is at the node of V3:

1: V3=10V-I×1KΩ

Second equation:

2: V3=I×1KΩ+Vgs1+Vgs2.

As far as can see from the information in the schematic, the transistors is the same, therefore Vgs is the same for the two: Vgs1=Vgs2. Same current through them.

The two equations can be solved for either Vgs or I. After that you use the formula: I=½×Kn×(Vgs-Vt)²

Always remember that this formula gives you two solutions and only one is correct.

I hope this makes sence and give the correct solutions. Let me know if this not correct.

Regards

 

[mohazaga]

Re: circuit analysis

hi ,
for the first circuit , the result come with me like the following : I=2.4385mA, so
V2=-2.5615 & V1=2.44, where the true result are V1=2.51V & V2=-2.79.
Plz, help me to figure out where the wrong
thanks

Added after 2 minutes:

Hi ,
I did not try 2nd till figure out the 1st.
help plz,
thanks


Added after 6 minutes:

hi
I down load the Sedra solution manual - 2 rar files
are both the same because when i extract it , its reslut same when i change the destination folder
thanks

Added after 2 hours 24 minutes:

hi
for circuit 2
Vgs1=Vg1-Vs1=V3-V4=10-I 1KΩ,
Vgs2=Vg2-Vs2=V4-V5=V4-I 1kΩ,
Vgs1=Vgs2,
V4-I 1KΩ = 10-I 1kΩ-V4,
V4= 5V,
I=½Kn(Vgs2-Vt)²=(4-I)²,
I=0.5615/2.4385 mA (2nd true),
then, V3=10-2.4387=7.5615 V,
V5=I 1KΩ = 2.4385 V
it's ok
Thanks

 

[tyassin]

Re: circuit analysis

Hi

I tried to use the "real" result of the first circuit. The solution does not make sense as the current you calculate, don't give you the voltage which is supposed to be right!!

But maybe you already found the solution

Regards

 

[mohazaga]

Re: circuit analysis

hi
thanks for reply , this a problem 4.44 in Sedra Microelectronics book (last eddtiton).
I solve with same procedure which u explain.
Do u have any another idea ?
thanks

 

[decent_witch]

Re: circuit analysis

can sombody plzz get me the solution manual for sedra and smith 5 th ed . i will be very thankful

Added after 5 minutes:

i have the solution manual for electric circuit 9 th ed

 

[starcoming]

Re: circuit analysis

As for the first fig, you can slove in this way.
Since Vg<Vd, nmos1 works in the saturation area.
I=1/2* k*(w/l)* (5-v1-1)^2...............(1)

As for nmos2, you can suppose it works in the saturation area too.
then get
I=1/2* k*(w/l)* (0-v2-1)^2...............(2)
I=(V2-5)/1.......................................(3)

Use (2) and (3), get
v2=-2.56
From the solution, we can see the suppose is OK.


then use (1) and (2)
get
v1=2.44

As for the second fig, since nmos1 (up) and nmos2 (down) have the same parameters and both work as diodes.
For them
Vds=Vgs-Vt
I=1/2* k*(w/l)* Vds^2
So
10-0=I*1K+I*5K+ 2*Vds
get
Vds=2.27V and I=5.15mA
and then V3, V4 and V5 can be gained.

 

[dinow]

Re: circuit analysis

hi, couldnt find solns to sedra book in e-book section.

Does anybody know how i can get this or if they have, please tell mee

Thank you

 

[Ahmed Ragab]

Re: circuit analysis

h**p://

Here is the link once again

 

[pollos30]

circuit analysis

the link dosent work! does anybody have the solution manual for microelectronics sedra sth edition?

 

[pollos30]

Re: circuit analysis

Is that the 5th edition for sedra?

 

[jawadasheikh]

Re: circuit analysis

Vgs=Vg-Vg. In your case Vg=0V and Vg=V2 other form.