# Amplifier design level shifting stage w/ current source equations

Discussion in 'Homework Help' started by wazzizit, May 30, 2015.

1. ### wazzizit Thread Starter New Member

Jan 14, 2015
19
0
Could anyone help by giving the equations used to calculate the resistor values in the circuit attached please?

Many Thanks

File size:
53.8 KB
Views:
20
2. ### Jony130 AAC Fanatic!

Feb 17, 2009
3,990
1,115
All transistor in your diagram are connected backward or simply you are using wrong transistor type.

3. ### wazzizit Thread Starter New Member

Jan 14, 2015
19
0
The top and bottom power supplies are the wrong way round. Assuming they're flipped, how do I derive the res values please?

4. ### Jony130 AAC Fanatic!

Feb 17, 2009
3,990
1,115
Well all you need is Ohm's law and two Kirchhoff's laws.
Ic2 = Ic1 = Ic3 = (Vd - Vbe1)/R1
And
Vo = Vi + Vbe3 +Ic3*R3

5. ### wazzizit Thread Starter New Member

Jan 14, 2015
19
0
Any chance you could sub in some values please? I'm struggling to know what the Vbe, Ic2, Ic1 and Ic3 values are

6. ### Jony130 AAC Fanatic!

Feb 17, 2009
3,990
1,115
You do not know what Vbe is ??

7. ### wazzizit Thread Starter New Member

Jan 14, 2015
19
0
I know it's the voltage from base to emitter...

8. ### Jony130 AAC Fanatic!

Feb 17, 2009
3,990
1,115
And typical Vbe values is ??

Jan 14, 2015
19
0
.7V?

Feb 17, 2009
3,990
1,115
Yes.

Jan 14, 2015
19
0

12. ### crutschow Expert

Mar 14, 2008
13,479
3,367
You need to take a stab at it before we can help.

The is Homework Help forum, not a Do Your Homework one.

13. ### wazzizit Thread Starter New Member

Jan 14, 2015
19
0
Please see my other thread where I have posted half of my efforts on this task so far.

Feb 17, 2009
3,990
1,115