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  1. L

    problem of fourier series

    I agree with Mr. Zero that a constant '1' is not a function of time. While it is true that a Fourier series can include a constant, would a constant with no harmonic components be recognized as a Fourier series? Interestingly, there are references to functions that are "singly periodic", with...
  2. L

    problem of fourier series

    Also, with period = 1 & 2 & 0.37 & pi & 1000 & .......... So what is the period? Can a signal be a function of 't' if it is independent of the value of 't'?
  3. L

    problem of fourier series

    I only see one signal that is a function of 't', and it is not a periodic signal.
  4. L

    area and average of periodic signals

    Why would you label the "area of periodic signal" as "Xavg"? If x(t) is a periodic signal, then the integral has only two possible values, zero & infinity. So in the second equation, 'T' must be infinity (and not the period of the signal as is normally implied).
  5. L

    resultant waveform

    Such a voltage squaring method is suspect. Power factor is determined by the phase angle between the voltage and current. If two voltages are to be related by a power factor, then they must have a common reference which is the current. Since power is the product of voltage and current, and the...
  6. L

    period of signal

    So if you would rather not do it the simple way, the question would be "How difficult do you want it to be?" Perhaps the challenge of limiting yourself to calculating on clay tablets with Roman numerals would be sufficient? Or a sufficiently antique method of numerical evaluation and graphing...
  7. L

    Capacitor and inductor reactance

    Units in the formula are Ohm, Hertz, and Henry. 50 μH = 0.000050 H.
  8. L

    Network theorems in Electronics ?

    Network theorems are the foundation of linear circuit theory. Linear circuits comprise R-L-C passive components and active devices having linear models including voltage and current sources. Circuits with non-linear devices such as diodes still obey the voltage and current laws, and can with...
  9. L

    resultant waveform

    That is not a correct assumption. The (1,0.8,0.6) power triangle applies to the first voltage (7V) only. The second voltage cannot be derived from the first voltage and the power triangle. Rather it must be worked backwards from the resultant voltage (11V). The law of cosines will still...
  10. L

    resultant waveform

    acos(0.8)=36.869898° sin(acos(0.8))=0.6 1²=0.8²+0.6²
  11. L

    resultant waveform

    Here is my view of the question as vectors and triangles. Is it correct to assume that when one waveform leads another, that the phasor is advanced in the counter-clockwise direction? The black lines show the problem statement, while the red lines show the power triangle.
  12. L

    Need help with H-bridge circuit running printer motor

    Since it seems to work OK without the load, the obvious problem would be that the 22KΩ base resistors are too large. Try 5600Ω or 4300Ω resistors instead.
  13. L

    discrete signals

    What is the smallest time interval that exists in nature? If there is no 'smallest interval' then time is continuous. Whereas for a discrete time signal, the smallest interval is the reciprocal of the sampling frequency and time is measured as integer multiples of the smallest interval.
  14. L

    RL Circuit

    Are you really sure about the 'correct' answer? That answer would have the current increasing to infinity yet the circuit would not seem to allow the current to keep increasing forever. Only a voltage source directly across the inductor would make the current increase with time without ever...
  15. L

    Electronic filter wheel mod for astrophotography, Need some help with the design :)

    If you are going the software controller route, then it may be worthwhile to investigate ASCOM compatibility. http://ascom-standards.org/Downloads/FilterWheelDrivers.htm But using a stepper motor presupposes a solid link between between the motor shaft and the filter wheel shaft so that an...
  16. L

    2 pole low frequency shelving filter design

    Maybe it would help to focus on the highlighted portion of your circuit:
  17. L

    2 pole low frequency shelving filter design

    Then look at the explanation in a different way. What if you were asked to calculate the voltage at each input pin? You have made V_Bias a variable voltage source, so the DC voltage on the '+' input equals V_Bias. Now suppose the DC output voltage of the amplifier is Vo, can you calculate the...
  18. L

    2 pole low frequency shelving filter design

    V_Bias sets the '+' input voltage. R13 & R14 form a negative feedback voltage divider for the '-' input. Because of the 100 dB DC voltage gain of the LM324, the offset between the '+' and '-' inputs will be in the range of 10 μV. So the common assumption is that both op-amp inputs are at the...
  19. L

    basic of control system

    1) Do the controlled physical systems typically have a low-pass response? Is the steady-state (zero frequency) value of the physical system important? 2) Testing circuit and system response can be accomplished with impulse, step, ramp, and parabolic inputs - each having a mathematical...
  20. L

    Voltage Divider +12V, -12V, Ground.

    Have you tried writing the node equation for this circuit? The circuit has only one node, with three branches.
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