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  1. R

    How can I set a frequency in a Wien bridge oscillator

    If you use two op amps, then only one variable resistor is necessary. Ratch
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    How can I set a frequency in a Wien bridge oscillator

    Nope, you cannot design a circuit helter-skelter like that. Since you have a inverting amplifier, you have to figure out what frequency the positive terminal of the op amp will be at 180° with respect to Vout. The total of the phase shift of 180° from the op amp inversion and the 180° from the...
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    capacitor and inductor

    The second statement. Sorry for the confusion. Ratch
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    capacitor and inductor

    Nothing happens instantaneously in the real world. If a step voltage occurs in a capacitor, then a current spike occurs. When does a voltage stop being a ramp and start to be a step in the physical world? Ratch
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    n-channel MOSFET common source amplifier

    For calculating K you are using a formula for the triode region of the MOSFET. Besides, you left out the Vds term. I think you want to use the formula for the saturated region which is Id = K*(Vgs-Vt)^2 , which gives K=0.006272 . Ratch
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    capacitor and inductor

    If dE/dt = I/C , then no current means the voltage holds steady. A large fast step of current increases the voltage rapidly until the current drops back to zero. Then the cap voltage will hold at new larger value. Ratch
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    capacitor and inductor

    I don't understand the question. In the capacitor by itself, the rate of change in voltage is proportional to the current. If you want a spike of voltage across the cap, then you have to apply a step of current. Perhaps you can give an example of what you mean. Everything takes a finite...
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    Op-Amp Gain ?

    OK, let's figure this out. Vi is the input, Vneg is the voltage on the negative terminal of the op amp, Vout is the output voltage, beta is the open loop gain. Vneg = Vo*(1/1001) and (Vi-Vneg)*beta = Vo . Solving the two equations for Vo/Vi, we get Vo/Vi = (1001*beta)/(1001+beta). Both the...
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    How to add 3 phasors?

    Google is your friend. http://en.wikipedia.org/wiki/Phasor Ratch
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    Circuit rectification help

    Do whatever the link shows you to do. The full adder is a very common logic circuit extensively covered in logic textbooks and other digital literature. Study it well. Ratch
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    Circuit rectification help

    Why don't you just Google for a full-adder? https://www.google.com/#q=full adder Ratch
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    What does impedance mean?

    Impedance is the frequency dependent opposition to current which a component or circuit has when driven by a sinusoidal voltage. Ratch
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    Phase Shift Oscillator

    You are right, I calculated it to be after the first section -55.77°. After the second section, it is -112.21°, and after the third section it is 180°. Ratch
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    Phase Shift Oscillator

    What I cannot understand is how the text book even suggested that formula. The calculated frequency using the sqrt(3) formula is always going to be wrong and different from the sqrt(6) formula no matter how the sections are loaded and coupled or not. And wrong by a ratio of 1/sqrt(2). Ratch
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    Phase Shift Oscillator

    LvW, No matter how you cut it, The sqrt(6) formula is going to give you a different frequency than the sqrt(3) formula. Ratch
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    Phase Shift Oscillator

    Laplace, I am suspicious of the blue curve above because a single section low pass filter with R=5 k and C=10 nf gives a break frequency of -45° of around 3 kHz. The above curve shows the break frequency of -45° at around 900 Hz. Here is my plot of it. Notice that the the -60°...
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    Phase Shift Oscillator

    Did you read posts #12 and #14 before making that statement? There are certain conditions that have to be met before you can just add on sections like that. Ratch
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    Which way does Electricity Flow?

    I can answer that one for you. First of all, the word "electricity" is too generic and has too many different meanings. In this case, if you want it to mean "charge carriers", then be specific and say charge carriers. In wires, the charge carriers are primarily electrons, so they are going to...
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    Phase Shift Oscillator

    Have you tried using a different simulator like the free LTSpice? Did you check out my derivation? The link below gives a similiar formula, but for the R's and C's interchanged. http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/oscphas.html Ratch
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    Phase Shift Oscillator

    k Because the 60° single section method relies on the successive section not loading the previous section. My method works no matter what the loading. Ratch
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