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14 votes
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How are RF filters constructed?

As you've discovered, once you are up in the 100MHz+ range, little is "simple". When using discrete capacitors and inductors, you have to consider their parasitic complements. Even basic ...
colintd's user avatar
  • 7,908
13 votes
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Do faster responding low-pass filters exist compared to a traditional RC filter?

Not exactly clear what you're asking, but if you use nonlinear components or active devices, what I think you're asking is possible. Consider this example circuit: The transistor push pull has a bias ...
bobflux's user avatar
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11 votes
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Opamp Non inverting Input

Page 33 of the data sheet (implied in the question) shows the image in the OP's question but, if you read the words in the DS below that image, they refer to another diagram (figure 36) where the op-...
Andy aka's user avatar
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10 votes
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Trouble with filter using Laplace transfer function in LTSpice

Save some grief: set \$\omega=1\$ Just save yourself some algebra grief and set \$\omega=1\$ when focused on a particular filter shape (like Bessel.) The filter shape can be moved around freely (at ...
periblepsis's user avatar
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10 votes

Do faster responding low-pass filters exist compared to a traditional RC filter?

I'll opt for a high-level explanation of signal processing here, and suggest where to go for further reading -- whole curricula exist around this topic, let alone stacks of papers and books, so I won'...
Tim Williams's user avatar
9 votes
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Anti-aliasing filter for 3.3 V ADC at 1 MHz

Defining the requirements for an anti-aliasing low-pass filter can be a little tricky and depends heavily on your use case. What's the problem we are trying to solve? Aliasing is the effect where ...
Mark Omo's user avatar
  • 643
8 votes
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Input filter LC for switching power supplies

With these types of filter I find that it's best to assume it will attenuate high-frequency noise based on a 1st order response (as if the inductor were replaced with a resistor) then, you put the ...
Andy aka's user avatar
  • 465k
7 votes

Input filter LC for switching power supplies

That's probably fine. A complete analysis requires much more information (voltage range, amount of ripple and noise, surge conditions if applicable, environmental, etc.), but these data likely don't ...
Tim Williams's user avatar
7 votes

Opamp Non inverting Input

Although an ideal op-amp will have zero input currents, a real op-amp will always have some current, called the input bias current on data sheets. For CMOS and other FET amplifiers, it can be very ...
Neil_UK's user avatar
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7 votes
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Part name of this IC - Analog Devices, 8-pin, "S 6B" A 06" "C 42"

Marking "S6B" : ADG721BRM Marking "A06" : AD8629ARMZ Marking "C42" : AD7787BRMZ pictures from LCSC:
vivier's user avatar
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6 votes
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How to improve the performance of my low pass filter design

The LMH6626 is not unity gain stable!
Tesla23's user avatar
  • 3,366
6 votes

Discrepancy between calculated and simulated cutoff frequencies of a bandpass filter

The circuit you show is a second-order bandpass filter. You cannot apply the classical design expressions pertaining to single-stage \$CR\$ or \$RC\$ filters, it is a common error. The reason is that ...
Verbal Kint's user avatar
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6 votes

Multiple resonance frequencies of common-mode choke

The model is just a model, and a simple one, maybe good up to the first resonating frequency, enough to maybe characterize the performance up to the rated frequency it is still useful. In real world, ...
Justme's user avatar
  • 159k
6 votes

Multiple resonance frequencies of common-mode choke

From the datasheet: they show a pair of two-layer windings. It's not clear how exactly they wired it for the test -- exact pinning, orientation, and even nearby materials, are critical at such ...
Tim Williams's user avatar
5 votes
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unfamiliar notch filter configuration

This is one of those interesting circuits. The upper amplfier, U1, is a differential amplifier. When redrawn, as below, the differential amplifier topology becomes clear. The Lower amplfier, U2, is a ...
qrk's user avatar
  • 10.3k
5 votes

General formula for the ripple voltage in a loaded bridge rectifier

What is the general formula to calculate the peak to peak ripple voltage and Vdc average of the voltage at the input of the 7805 voltage regulator in a circuit like this? The general formula should ...
Kuba hasn't forgotten Monica's user avatar
5 votes
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strange phase behavior RC low pass filter

Electrolytic capacitors have fairly large ESR values, and they're fairly constant across frequency. As the reactive impedance drops according to frequency, the total impedance becomes dominated by ...
Cristobol Polychronopolis's user avatar
5 votes
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Square wave of oscilloscope for RC circuit

That in-scope square wave generator will be fine. Measure its output resistance, as that will add to the effective value of any series R you are using with your C. Do that by loading it with a ...
Neil_UK's user avatar
  • 169k
5 votes

Multiple resonance frequencies of common-mode choke

Transistor models becoming less resembling subcircuits and more like fitted approximations, models of magnetics follow suit. Wurth's model of 744830017132 does not show high-frequency peaks of the ...
V.V.T's user avatar
  • 4,357
5 votes

AC line filter polarity

Yes. They are symmetrical. You can hook up the line leads any way and the load leads any way.
MOSFET's user avatar
  • 4,983
5 votes

RC or RL high pass audio filter?

inductive filters are rarely used because: they are physically bigger, particularly for filters at low frequencies, which you need for audio coils are more expensive coils are susceptible to external ...
danmcb's user avatar
  • 7,298
4 votes
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Sigma-delta modulator (ADC), can it be used without sinc3 filter?

Is it possible to work without a sinc3 output filter Not really in the way you are thinking. You really need to sample every bit coming out and low-pass filter that data stream. The low-pass filter ...
TimWescott's user avatar
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4 votes
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Difference LowPass Filter

Well, first of all (as @nohu42 and @Electrocol explained) you need to use a buffer circuit which is not the one you showed. Now, let's assume that you used the correct buffer circuit. Let's call the ...
Jan Eerland's user avatar
  • 7,989
4 votes

Trouble with filter using Laplace transfer function in LTSpice

I suppose that the mentioned frequency (f=3.5 kHz) is the desired 3dB-frequency (your requirement), right? In this case, it is not true that the corresponding w value (2Pi*f) would appear in the ...
LvW's user avatar
  • 27.4k
4 votes

Active low-pass filter design

As said by others in the comments, numbers m and n are YOUR choices to attempt to get at least some of the resistors and capacitors available as standard off the shelf components such as resistors 680 ...
unawriter's user avatar
4 votes
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Parallel resistors with polarised capacitor

If I am right, is there anything specific I need to take care of before using the filter in my SMPS? You are correct in that they are used to balance the voltage on the capacitors. This is important ...
jpa's user avatar
  • 8,843
4 votes

Switch debouncing

10µF with 1k make the time constant 10ms. The low quality buttons bounce about 10ms. There is also a high chance the bounce occurs right at Vcc/2 (when logic flips) so you will never debounce 100% ...
Michal Podmanický's user avatar
4 votes

Can 60Hz notch filter remove inteference current on input leads in high impedance electrodes?

As already said, the purpose of a notch filer is to remove a tight frequency range so it will in theory remove the interference. However practically it might not be that simple. If you apply the ...
DELTA12's user avatar
  • 888
4 votes

Do faster responding low-pass filters exist compared to a traditional RC filter?

For this case, rather than a filter you might use a comparator with the threshold set to below the noise. This would basically reshape the pulse, eliminating the noise. For 500ns pulses it would need ...
GodJihyo's user avatar
  • 25.1k
4 votes
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Wideband Impedance Matching for Inductive Source/Load

Take a look at the following two examples of common emitter, 50 Ohm I/O preamplifiers. The first one, with current and voltage feedback, is broadband, has medium gain and doesn't need much power. The ...
Raonoke's user avatar
  • 721

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