Recent content by cyeokpeng

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    Reading frequency spectrum / Fourier Transform and Power Spectra

    Your questions are a bit unclear. If you want to interpret the power spectrum, nasu has already interpreted it for you. I would just like to add on a bit. The frequency spectrum pattern clearly shows a periodic signal in the time domain. This is because of the presence of the impulse function...
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    Linear programming: simplex question (might belong in precal)

    Hi, Hopefully, I am not late to help. After performing the row (pivot) operations, remember to update the "a", your cost coefficient of the entering variable x3 into the 3rd row, i.e. now "a" for the 3rd row is updated from 0 to 60! I think this is what causes the error in your Simplex...
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    Linear programming and the two phase method

    To put it simply, the main advantage of the two-phase Simplex method is: in LP problems with equality in their constraints, and >= constraints (which usually occurs in a minimization problem), we need to use big M cost coefficient in the objective function for introduction of artificial...
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    Can State University Maximize Tuition While Meeting SAT Requirements?

    Oh, I didn't think of that. So the min. standard for average SAT score 1150 is for the whole university! So that makes sense, and the constraint formed is much reasonable! Thank you!
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    Can State University Maximize Tuition While Meeting SAT Requirements?

    The admissions office at State University wants to develop a planning model for next year's entering freshman class. The university has 4500 available openings for freshmen. Tuition is $8600 for a local student, and $19200 for an overseas student. The university wants to maximize the tuition...
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    Combination Problem: Selecting 6 Roses of 3 Colors

    I got this problem, don't know how to solve. Of 10 variety of roses, 3 are pink, 5 are red and 2 are yellow. Calculate the number of ways in which we can select 6 roses, so that in the selection, at least one rose of each color is included. ?
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    Can Negative Feedback Improve Amplifier Performance?

    An additional property of negative feedback you never mentioned is NOISE REDUCTION performance. 5. Increase in input resistance This is not necessary true! It depends on the actual feedback topology you employed in the amplifier circuit. Basically, you need to apply voltage feedback to...
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    Can Negative Feedback Improve Amplifier Performance?

    Quick Math Proof: 3. Increase in gain stability / Gain Desensitivity Consider closed-loop gain = open-loop gain / (1 + open-loop gain*B) Af = A / (1 + AB) Applying calculus approximation method, d(Af) = dA/(1+AB)^2 Divide by Af, d(Af)/Af = (dA/A) * (1/(1+AB) only accurate for...
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    Can Negative Feedback Improve Amplifier Performance?

    Quick math proof: 1. Reduction in Gain Closed-loop gain = Open-loop gain / (1 + Open-loop gain*B) where B = feedback factor > 0 Can be derived from Transfer Function analysis as you can se fro the relation, the denominator > 1, so Closed-loop gain is...
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    Qn5What is the purpose of using a self-biased circuit for MOSFET amplifiers?

    Hi, I know how to bias a BJT transistor to operate in the active region, so that the amplifier circuit can operate as a small-signal amplifier. Two methods (i) Use biasing resistors to form a self-biasing circuit. (ii) Use diode biasing, coupled with biasing resistors. Qn1 However, how...
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    How does the varying resistor affect the voltage at node 2?

    Hi, I forgot my nodal analysis learned during 1st year, but I can give you some light on the 100 ohms varying resistor. Whether the varying resistor is 100 ohms or 1kohms is of no concern in the amplifier circuit because it effectively acts as a potentiometer OR potential divider. Whatever...
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    Troubleshooting 9V and 1 Ohm Resistor Connection

    What 9 V voltage source are you using? Is it a dry cell or a lab power source? How do you connect the ammeter to test the current?
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    Are Voltage Sources and Current Sources Interchangeable in Transistor Circuits?

    Something I am still not sure: The lead acid car battery is a voltage source, that means it supplies a constant voltage within a certain range of current flowing through it. However, in the real world, I understand that the car accumulator, like most batteries, have a max. current limit they...
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    Are Voltage Sources and Current Sources Interchangeable in Transistor Circuits?

    That means you can set it to be a constant voltage source or current source depending on the application you want. That is cool. What about a normal dry cell battery, or even 12V lead acid battery, are they voltage sources or current sources?
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    Are Voltage Sources and Current Sources Interchangeable in Transistor Circuits?

    Just curious: The DC power supply in most labs are voltage sources or current sources? I think it should be a voltage source (a practical voltage source modeled as an ideal voltage source in series with a source resistance of 50 ohms) because when I test the power source in the lab with a DC...
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