An op amp circuit is to be designed in which the relationship between the output voltage v0(t) and the input voltages Va and Vb is given by: The circuit for which this relationship holds is shown below. Assume there is no energy stored in the capacitors at the instant the switches close. Also, assume the op amp is ?deal. Determine values for the circuit components (R and C) in order to satisfy the output voltage equation shown above. Note that realistic values in k ohm and mu F or mu F must be used. Also note that assumptions are to be made and that there are several options for this design. Determine theoretically and confirm from the plot of v0(t) in P Spice how long (in m sec) it will take to saturate the amplifier. Solution Applying fundamental principles to the circuit, we can get, (v a -0)/R + (v a -v o )/(1/wC) = 0 Also for the second input, (v b -0)/R + (v a -0)/(1/wC) = 0 Now, substituting, v 0 as given in the question, suitable values of practical R & C can be found out from the basic equations which satisfy the fundamental principles. .

1. An op amp circuit is to be designed in which the relationship between the output voltage v0(t)
and the input voltages Va and Vb is given by: The circuit for which this relationship holds is
shown below. Assume there is no energy stored in the capacitors at the instant the switches close.
Also, assume the op amp is ?deal. Determine values for the circuit components (R and C) in
order to satisfy the output voltage equation shown above. Note that realistic values in k ohm and
mu F or mu F must be used. Also note that assumptions are to be made and that there are several
options for this design. Determine theoretically and confirm from the plot of v0(t) in P Spice
how long (in m sec) it will take to saturate the amplifier.
Solution
Applying fundamental principles to the circuit, we can get,
(v a -0)/R + (v a -v o )/(1/wC) = 0
Also for the second input,
(v b -0)/R + (v a -0)/(1/wC) = 0
Now, substituting, v 0 as given in the question, suitable values of practical R & C can be found
out from the basic equations which satisfy the fundamental principles.