KCC Quizzes AQQ303 about the radius of a circle
1. Quote of the month: "When I die, I want to die like my grandfather who died peacefully in his sleep. Not screaming like all the passengers in his car" - Will Rogers
2. Quiz AQQ304 about finding the radius of a circle
Good luck, and try to be
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August Monthly Blog Quiz! Read the blog, take the quiz, and you could win a gift card
Important: Read the blog first . The quiz questions are all based on the content of the blog:
Stay in the loop and win! Read the blog Current Output Driving Industrial Loops , then take our quick five-question quiz for a chance to win a gift card
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New challenge is here! It's AQQ259 related to a tunable or adjustable amplifier:

The above circuit is a tunable or adjustable gain amplifier. The opamp used is
considered as ideal (i.e. infinite open loop gain, infinite input resistance and
zero output impedance).
Questions:
1. For given R1, R2 and P, at which wiper position α, Vout = 0 volt?
2. Versus Vin, what is the dynamic range of Vout?
Good luck! And try to be among the first ones!
P.S. Don't hesitate to spread those weekly quizzes to colleagues or friends (we need more participants)!
1. Vout is 0V at α = R2/(R1+R2)
2. at α = 0: Vout = -Vin * R2/R1
at α = 1: Vout = Vin * (1-(R2/R1))
...and of course, Vout is limited to +Ecc max. / -Ecc min.
Thanks Roland! Agree with your answer 1. But are you sure about question 2? You probably made a typo in an equation when calculating Vout for alpha=1... May be you can recheck?
Thanks Roland! Agree with your answer 1. But are you sure about question 2? You probably made a typo in an equation when calculating Vout for alpha=1... May be you can recheck?
Oops, I see: The correct answer for α = 1 is Vout = Vin
... but this is only true as long as R1 / R2 is > 0 ...
And if R1=R2 you have a nice use case: With the potentiometer you can adjust the gain from +1 to -1. In the mid position the gain is 0.
Well recovered ADIApproved