Operational Ampifier Applications

Question 1

What is a summation amplifier?

Answer 1

An amplifier circuit which has multiple sources connected to the inverting terminal and a non-inverting terminal connected to ground

Question 2

How do you find V(o) in a summation amplifier?

Answer 2

Apply KCL to the node where all the input currents meet the feedback current in terms of V(1) then rearrange the expression to get an expression for V(o)

Question 3

What’s the V(o) expression when all input resistances in a summation amplifier are equal?

Answer 3

V(o) = -R(2)/R(1) * [V(in1)+V(in2)]

R(2) being the feedback resistor

Question 4

What should you do in order to invert the sign in an OP-AMP circuit?

Answer 4

Attach an second inverting OP-AMP to the output of the first with a resistance equal to the feedback resistance of the second OP-AMP. The goal is to get a gain of -1.

Question 5

What is a practical integrator?

Answer 5

A OP-AMP with an input at the inverting terminal with a grounded non-inverting terminal with a capacitor and resistor in parallel in the feedback loop

Question 6

What is the gain in a practical integrator circuit?

Answer 6

|V(o)/V(i)| = R(2)/R(1) * 1/sqrt[1+(ωR(2)C)^2]

Question 7

How can we guarantee that an OP-AMP works as an integrator?

Answer 7

Let the input signal f(s) be 10 times f`