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Questions tagged [passive-filter]

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0
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3answers
51 views

How to combine a LPF and a Voltage divider?

I have to connect a 5V analog signal to a 3.3V MCU analog GPIO input as shown in the attached image. I wonder if its possible to combine the 2 blocks of voltage divider and RC-LPF into a single block? ...
1
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2answers
48 views

Filter capacitors to avoid pop when hitting footswitch

This is an audio circuit question. I have two line level signals going into two DIs going into a PA. I want to craft a custom passive mute switch, sometimes when debugging feedback when performing ...
0
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1answer
54 views

What is the purpose of the upper inductor in this speaker diagram?

What is the upper inductor symbol in series with the woofer used for in the below diagram? It seems the tweeter and the woofer are both I guess 8 Ohm and that's why the 4 Ohm parallel equivalent ...
1
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1answer
104 views

Why did C2 fail?

I'm trying to run a Raspberry Pi as a remote controller and timer for a diesel water pump but it keeps rebooting when the engine cranks. I checked and the supply doesn't drop below 10.5V during ...
0
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0answers
51 views

PWM to sinusoid with LC filter

I am studying a three-phase inverter with output LC filter (as shown). I want to get 12VAC 50Hz sinusoidal wave at output of LC filter (at load) Vdc=48V fs=10kHz switching freq. Load=13.8 ohm ...
5
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6answers
547 views

RC Lowpass Filter between Amplifier and ADC input

I have sensors (pyranometers that consist of thermopiles and measure sun irradiation) that ouput a low voltage signal so I need to amplify them using an instrumentation amplifier. I have chosen the ...
0
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0answers
25 views

When is a differential choke preferred to an LC filter and vice versa?

Both single LC and differential choke are used for attenuating differential mode noise. I only know that LC filter has resonance issues. Is that the only reason a differential choke is preferred? ...
1
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0answers
42 views

What are the important specs for inductor in passive tone control?

I'm pretty much an electronics newbie. I'm working through some circuits in "Electronic Projects for Musicians". It has a "Passive Tone Control" which seemed like an easy start. Unsure if I can ...
0
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2answers
48 views

How to smooth changes in *current* in a current meter?

I have a milliammeter I'd like to debounce with an \$f_c\$ of say 0.1 Hz (10 s) to where it reads a mean average rather than however fast the needle moves, dampened only by physics. Vcc is about 8-9 V ...
1
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2answers
92 views

Is this symbol for common-mode choke or usual inductor?

In the below circuit from this datasheet, I think L1 represents common-mode choke; but what does L2 represent? And in this datasheet for a similar filter, I don't see any difference between the ...
0
votes
1answer
105 views

Input impedance of low pass filter on LTspice must be constant in it's pass band?

I have single supplied sallen-key filter more that have nice 3MHz flat LPF response. I tried to compute the resistance directly by dividing the input voltage by input current which is the voltage and ...
1
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2answers
104 views

Modelling 3-phase induction motor and filter for inverter output in LTspice

I am designing an inverter in Ltspice and am looking to have a simple circuit to represent the motor load and filter out the PWM harmonics in order to obtain outputs. The motor characteristics are: ...
0
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1answer
45 views

Unexpected output for a passive filter circuit with low ohm resistor

With a simple filter circuit (either high pass or low pass), I'm seeing unexpected behavior in the o-scope output when I use a resistor with a low ohm value (e.g., 10 Ohms). Since a picture is worth ...
0
votes
1answer
67 views

Easiest way to find transfer function of a lossless ladder filter after we finish design?

I have completed my Lossless Ladder BPF design, but I don't know how to find the transfer function of the resulting circuit without going through the slow and rigorous process of getting resistances ...
1
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2answers
194 views

Low Pass Filter Wrong Pole Location

I wanted to understand and derive an equation of simple low pass filter that shows the location of pole in frequency response graph (Bode plot). So, here is the derivation: $$V_{OUT}=\frac{V_{IN}*...
1
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2answers
52 views

How much is the permeability of this attached inductor core?

I want to use this inductor for AC line filter as line reactor. Its inductance value is 6 mH but I don't know the exact value of permeability of the material. It will be used with VFD at the input to ...
0
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1answer
51 views

how to design AC line filter for VFD?

I am working on VFD for single phase induction motor. I am rectifying AC 220V directly to DC link capacitor. There is no LC filter from AC mains. There are harmonics in the AC mains. Can you suggest ...
0
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1answer
58 views

Problem related to the transfer function of RC low pass filter

I have the following question: For the passive RC low pass filter shown below: $$V_S(t)=\cos(t)+\cos(100t)$$ $$V_0(t)=\alpha\cos(t+\theta)+\beta\cos(100t+\phi)$$ (where \$\alpha\$, \$\beta\...
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2answers
367 views

Cutoff frequency of a second order low pass RLC circuit

L = 25 mH, R =1 kOhm, C = 10nF and Vs(t)=sin(wt)V, freq = 500 Hz I am trying to calculate the cutoff frequency of a second order low pass RLC circuit I don't know if I can still apply the formula of ...
0
votes
1answer
54 views

Inductor choice for passive filter

I need to design a band-pass passive filter with pass band 10kHz~150KHz. One of the needed inductor is 2.2mH. I find there are two choice: Axial type or Can type. But it seems they are designed mainly ...
0
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2answers
445 views

Second Order Passive RC Low Pass Filter Doesn't Have -6dB at cutoff Frequency in LTSpice

For Second-Order RC filter the cutoff frequency is: $$fc = \frac{1}{2\pi \sqrt {R_1C_1R_2C_2}}$$ I have taken R1 = R2 = R = 1K Ohm and C1 = C2 = C= 0.1591 micro Farad. So the cutoff frequency comes ...
5
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1answer
112 views

Design of cavity filter

I try to design a Chebyshev bandpass filter for 6 GHz as a coaxial cavity filter. I know that the filter can be designed with the aid of the coupling coefficients between the resonators and the loaded ...
-3
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1answer
67 views

Where is the dc component?

So a ac filter doesnt allow the dc component to pass through it, so the dc component would take a altetnative path where as the ac component would easily pass through it. My question is, where is dc ...
0
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2answers
105 views

What does this RC network do in this audio transformer output stage?

This is a relatively well known ABY circuit available on the internet. CLICK HERE, REMOVED IMAGE FOR COPYRIGHT REASONS I have two questions about this circuit : 1) What does the RC network (in the ...
0
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2answers
63 views

RC Waveform output signal confusion

I've been struggling to understand how filter capacitors specifically low pass filters achieve their output signal waveform. If I take the example from https://www.electronics-tutorials.ws/rc/rc_3....
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2answers
45 views

Transmittance of a capacitively coupled shunt resonator

I have been trying to understand the expression of |s21| for the resonator mentioned in this article. For a circuit similar to the drawn below, in which R1 is used as the temperature sensitive element,...
0
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2answers
91 views

Capacitively coupled shunt resonator

The diagram below shows a capacitively coupled parallel RLC resonator. Through simulations I observe that C2 and C3 influence the resonant frequency . I'd like to obtain the analytic expression for ...
0
votes
2answers
192 views

Transfer function of a bandpass

i was doing some homework and one thing I had to do was to derivate the transfer function of a given bandPass. I have done it myself but i dont know if it is correct nor if i followed the right path / ...
3
votes
2answers
270 views

Passive Low Pass Filter

What I want to do is make a low pass filter using a simple RC circuit (first order), or possibly an LC circuit (which would be second order). Right now, I am in the process of determining the values ...
0
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1answer
69 views

Pre-Amplifier Question [duplicate]

back at it again with a problem that I am stuck on and need some clear explanation of. 1/2: I was wondering How those Bass controls work, for example the ones in the car you allow to change the bass ...
0
votes
4answers
453 views

Chosing R and C values for a given RC filter design

I'm currently into designing passive LP filters such as RC topology and active filters such as Sallen-Key topology. I'm fully aware that what matters in the choice of values for the resistors and the ...
1
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3answers
175 views

Influence of I/O impedance in Butterworth passive filter design

I'm using a simple online simulator tool to build a passive Butterworth filter. An affirmation made in this page confused me: Enter the filter characteristic impedance. In all cases, unless you ...
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0answers
32 views

Synchronus dcdc converter shunt RC filter design

I'm struggling to find a guide/application note or whatever that explains the calculation, considerations and layout of an RC filter for current sensing on a synchronous DCDC converter (like the ...
0
votes
1answer
47 views

High power highpass filter

I'm using an audio amplifier to produce a 15-20 kHz, 6 watt sine wave output into a pure resistive load. There are some low-frequency components to this signal that I want to remove (mains frequency ...
1
vote
2answers
58 views

How can I size the 'supply noise filtering' capacitors at the load end for this scenario?

There is this SMPS dual-power supply which needs to power a load outdoors around 100 meters far away via a 3-wire cable as shown below: simulate this circuit – Schematic created using ...
2
votes
1answer
498 views

Frequency response of a parallel RC filter (smoothing capacitor in rectifier circuit)

I understand qualitatively and electrically how a smoothing capacitor works in the case of a diode-based full-bridge rectifier but what I am not too certain of is how to describe it in terms of its ...
1
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2answers
67 views

Configuring Frequency Bandwidth and Input Signal for Bandpass filter circuit

How do I set and configure the frequency bandwidth I want the filter to output to a device? I am using a physical passive bandpass filter which I intend to take the signal in and filter it and output ...
0
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2answers
83 views

RC Filter measured response differs from calculated transfer function

I've created a first-order RC filter with R = 68 Ohm, C = 5.0 uF, and I am studying the transfer function of this filter. I have calculated the transfer function to be 1/(1+jwRC), based on the ...
8
votes
1answer
290 views

Parallel RC filter on SCR gate

I came across an old circuit from work that discharges a capacitor (C1) into a step-up transformer to a low-impedance load. This event is triggered by a pulse into an SCR, whom has a parallel RC ...
0
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2answers
338 views

I need to design a bandpass filter by cascading passive high pass filter and passive low pass filter

I have a low pass filter with 3db cut off frequency of 200Hz and a high pass passive filter with 3db cut off frequency of 2kHz. I need to design a cascaded band pass filter which will isolate ...
0
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0answers
70 views

explain 12 pulse rectifier output and filter circuit?

Parameter 3 phase 115/200 volts AC Input 200-amp output Input Frequency is 400 DC output is 28 volts Output ripple is 1.5-volt maximum Question : on transformer secondary side it is star and ...
1
vote
1answer
129 views

Change in gain and cutoff frequency of 2nd order passive filters due to amplifier circuit

I'm designing an simple equalizer for a first course in Electric Circuits and having some problems. Circuit diagram and AC Sweep Simulation (Multisim 14): Circuit Diagram AC Sweep Simulation The ...
0
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1answer
224 views

Quality factor limit for 2nd order RC passive band-pass filter

simulate this circuit – Schematic created using CircuitLab I'm designing a 2nd Order passive RC band-pass filter and found that the quality factor is given by: \$Q=\frac{\sqrt{C_1C_2R_1R_2}}{...
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0answers
49 views

Butterworth component quality

I'm working my way through Bowick's RF Circuit Design. In the resonant circuit chapter he does a great job of describing how component Q affects circuit Q, and how loaded Q works. There, you set the ...
1
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2answers
182 views

RC Filter Parallel Potentiometer

I am trying to teach myself electronics, namely audio filtering, and I came across this circuit. Now with my limited knowledge the 'volume potentiometer' (that's what it is explained as) seems to be ...
14
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8answers
3k views

Why, in a passive circuit with a sinusoidal input, do all voltages and currents have the same sinusoidal behavior as the input?

I am familiar that in any circuit composed of linear passive elements and a sinusoidal input, all voltages and currents through and across any element will exhibit the same sinusoidal behavior and ...
1
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1answer
63 views

How to set up signal generator in lab to obtain an output voltage?

In one of my laboratory assignments, I am to study how to work with square signals in RC circuits (low pass filter). Please keep in mind this is an introductory Electronics course. Basically, I am ...
0
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2answers
669 views

Transfer function for a Passive Second order Low-pass Filter and to determine the components values

I am working on an assignment about Passive, second order low-pass filters. Cool little things if you get to know them. We are given the placements of the passive components (Inductor(L1), ...
0
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1answer
46 views

How is the voltage across a capacitor measured in a passive LPF circuit with no ground?

Say we have a low pass filter circuit as the one that follows: If I want to study how the charging/discharging of the capacitor works, I need to apply the universal equation for voltage. However, ...
0
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1answer
52 views

Can't draw bode curve of this zero

I have a transfer function like this: \$H(s)=\frac{s^2+\frac{1}{LC}}{s^2+s\frac{R}{L}+\frac{1}{LC}}\$ I can separate the denominator into an expression of the type: \$(1+s/a)(1+s/b)\$ and then plot ...