# Tag Info

### 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:
• 15.1k

### 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 ...
• 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}\...
• 7,403
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 ...
• 521
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 ...
• 78.1k
1 vote
Accepted

### 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 ...
• 10.6k

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