EE Pro for TI - 89, 92 Plus
Equations - OpAmp Circuits
71
Rout
Rs
Av
=
⋅ +
1
b
g
Eq. 26.3.3
Example 26.3 -
A current amplifier with a 200 k
Ω
feedback resistance has a voltage gain of 42.
If the source resistance is 1 k
Ω
, the load resistance is 10 k
Ω
and the output resistance of the OpAmp is 100
Ω
, find
the current gain, input and output resistances.
Entered Values
Calculated Results
Solution -
Use all of the equations to compute the solution for this problem. Press
„
to display the input screen,
enter all the known variables and press
„
to solve the equation. The computed results are shown in the screen
displays above.
-PQYP8CTKCDNGU#X
4H
AM
Ω
4N
AM
Ω
4Q
A
Ω
4U
AM
Ω
%QORWVGF4GUWNVU
#KE
4KP
A
Ω
4QWV
A
Ω
26.4 Transconductance Amplifier
The two equations in this section specify a closed loop transconductance Agc and output
resistance Rout in terms of the resistance Rs and voltage gain Av.
Agc
Rs
=
1
Eq. 26.4.1
Rout
Rs
Av
=
⋅ +
1
b
g
Eq. 26.4.2
Example 26.4 -
Find the transconductance and output resistance for a transconductance amplifier with a voltage
gain of 48 and an external resistance of 125
Ω
Entered Values
Calculated Results
Solution -
Use both equations to compute the solution for this problem. Press
„
to display the input screen, enter
all the known variables and press
„
to solve the equation. The computed results are shown in the screen display
above.
-PQYP8CTKCDNGU4U
A
Ω
#X