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2 votes

Issue with 3rd order Butterworth low pass filter simulation

Attempt #2 will work if you do the math properly. You need to use complex numbers. \$ s = j\omega \$ I don't use Matlab. Excel is clumsy for this purpose, but it works. With formulas shown:
Mattman944's user avatar
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2 votes

Trouble with filter using Laplace transfer function in LTSpice

The Bessel coefficients from Wikipedia yield a filter with unit group delay, not unit cutoff frequency. It is thus not surprising that you don't get the cutoff frequency you expect. What is your ...
John Doty's user avatar
  • 2,565
1 vote

Find resistors for an inverting op amp band pass filter

Well, the transfer function of your circuit is given by: $$\mathscr{H}\left(\text{s}\right):=\frac{\displaystyle\text{V}_\text{o}\left(\text{s}\right)}{\displaystyle\text{V}_\text{i}\left(\text{s}\...
Jan Eerland's user avatar
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1 vote

Reason to increase output impedance in a non-inverting op-amp

Capacitance to ground at the output of an op amp acts with the output resistance to add a pole to the loop which can destabilize the amplifier. One technique used to improve stability in the situation ...
user350400's user avatar
1 vote

Reason to increase output impedance in a non-inverting op-amp

This type of scheme is to decrease the amount of capacitance that the opamp "see's" on it's output, if you were to decrease the series resistance beyond a certain point on the output its ...
Voltage Spike's user avatar
  • 78.1k
1 vote

Why would a low-pass filter be connected to +5V on an RS422 differential line?

In a multi-node network, the RS422 drivers each have tri-state outputs that can go into a high-impedance state to allow other drivers to drive the bus. When all of the nodes are in this state, the ...
John Birckhead's user avatar

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