Questions tagged [high-pass-filter]

A high-pass filter is an electronic filter that passes signals with a frequency higher than a certain cutoff frequency and attenuates signals with frequencies lower than the cutoff frequency.

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27 views

Transistor Amplifier Signal Drops Off Below 200-300Hz

I tried to build a dual transistor amplifier from a schematic I saw, and used AC Analysis in LT Spice. What I found was that the current and voltage at my simulated 8 ohm speaker load was dropping off ...
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84 views

How to find a amplifier that named “ISP” on a circuit?

I am analyze the circuit. I can't find any relation about the name ISP of a op-amp. When we look the high pass filter we see there "ISP" name. I search it on google but I can't find nothing ...
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33 views

how to design the instrumentation op amp and filter circuit for 0.5-30hz

Did I get the image from an article. how to design such a circuit
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43 views

best high pass filter topology to extract low V kHz range pulse from noisy 60Hz line voltage before daq

I need to extract a 1 kHz-10kHz range voltage pulse created by a current pulse I inject on an harmonic rich 60 Hz network and that propagates on it. The line voltage is 120V AC. harmonics 2 and 3 are ...
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67 views

Detecting small AC current signal generated by phototransistor

I'm trying to detect a small AC signal (~10kHz) generated by a phototransistor on a magnitude of 10nA~1uA using the following circuit by converting the signal to voltage signal first and then filter ...
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46 views

Question about filter transformation

I'm studying filters. In particular, I'm studying low-pass to high-pass filter transformation. I know that you only need to design an equivalent normalized low-pass filter and then, by using a ...
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43 views

How to apply high gain to filtered signal without shifting voltage level?

I have an op amp gain circuit at the output of a 2 stage filter. It seems like at high gain settings (x500), the steady state voltage shifts significantly. I am trying to keep it at ~1.7V and it ...
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31 views

TPA0253: Help Understanding Mono Output

I'm working on implementing an audio amplifier into a circuit design, and I am trying to understand the output configuration for the speaker using the TPA0253. I will be using a 8 ohm, 1W speaker for ...
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92 views

Band-pass filter vs. Serial Low-pass+High-pass filter - Is there a difference?

Is there a difference between a band-pass filter (BPF) and tying a low-pass filter's (LPF) output to the input of a high-pass filter (HPF)? It seems to me that they should do the same thing---or ...
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34 views

High pass filter that locks voltage at certain amount until frequency is reached

I have a sine wave that is biased at about 1.5V DC. I want to create a high pass filter that allows any frequency through greater than 4000Hz. Want I want my high pass filter to do is to be at 1.5V ...
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42 views

What change should I make in my Lead Compensator circuit below to reduce the DC response? Vin be sine wave with variable frequency

I want to increase my cutoff frequency, Fc. As Fc=1/2piR*C, Should I reduce the value of either resistor or capacitor to increase my cutoff frequency?
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48 views

Why does this high pass filter behaves like band-pass filter on Multisim AC Sweep simulations?

I have this high-pass filter schematic and its AC Sweep simulation. Until the break through the end, the graph is right but I can't see why the graph breaks on the right hand side and filter behaves ...
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19 views

Shared via on 22pF cap only used to smooth differential clock signal?

Google's so cluttered these days, it's hard to find simple answers. I've got differential clocks running around 500MHz (1000Ms). There's some optional 22pf caps on each Address line, going to the ...
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84 views

Finding transfer function and tuning cutoff frequency of High-Pass FIlter

I have a schematic for a High-Pass filter that has a cut-off of around 7Hz. I obtained the designed online and want to tune it to have a cutoff of 5Hz instead. I assumed I would proceed in the ...
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286 views

High pass filter - Cut-off frequency calculation doesn't match simulation

I have made the following simulation with the circuit you can see below: I'm asked to find the cut-off frequency for this filter. From the simulation, it looks like it \$f_c = 500 \text{Hz}\$ or ...
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47 views

Dielectric absorption in capacitor (audio crossover)

I want to understand the selection of a proper capacitor type for a simple audio crossover (passive lowpass filter before woofer, passive highpass filter before the tweeter). Various blogs more or ...
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30 views

LM386 High Pass Filter Design? [duplicate]

I was looking into the datasheet for the LM386, and they provide an example implementation circuit. At pin 5, as I understand it, you can expect an amplified signal with a DC offset of Vcc/2. I can ...
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65 views

Analysis of a high-pass filter

I'm doing some analysis of op-amp circuitry including the high-pass filter shown below. I was given three questions to try further my understanding on the analysis of such system. However, I am ...
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50 views

How to derive the gain (ratio of output voltage to input voltage)

$$ \frac{V_c}{V_s} = \frac{\frac{j}{\omega\cdot C}}{R+\frac{j}{\omega \cdot C}} $$ Given this starting formula, how to rationalize the denominator and find the gain?
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52 views

How is dc restorer circuit used for PWM demodulation/detection?

In the Microelectronics Circuits textbook by Sedra & Smith, it is said that: As an application, consider a pulse signal being transmitted through a capacitively coupled or ac-coupled system. ...
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30 views

Fitting to attenuation and phase shift curves for a low-pass and high-pass filter?

I'm sure this is something super basic, but I'm struggling a lot. I did a lab for my circuits class where we took a low-pass filter and high-pass filter circuit, and we recorded the input/output ...
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71 views

How to calculate cutoff frequency for a high pass filter in DC biasing circuit

I would like to DC bias an AC signal using a voltage divider as shown in the following schematic. I realise the bias point would be subject to noise from the power rails, but that is not a concern for ...
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100 views

how to design a low pass filter for square waveform

I have square wave signal of 100KHz with few high frequency ringing from 555 timer.when i tried to use a 100KHz first order rc low pass filter,i got a sawtooth waveform because the 100KHz square will ...
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427 views

How to remove DC offset (and make average DC value 0V) from ADS1261 square wave AC-excitation circuit

I am attempting to remove the DC offset from the 1 kHz, ± 2.5 V, AC square wave output pins of an ADS1261 (http://www.ti.com/lit/ds/symlink/ads1261.pdf). However, when measured on the oscilloscope (...
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43 views

PMOS unexpectedly passing current with capacitor on drain

I am designing a circuit to get a pulse when a switch opens. When the voltage source V1 is connected, the switch SW1 starts closed. I want Vout to briefly go high when SW1 opens. The circuit I ...
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384 views

Low pass filter not working properly

This is the pass band that I'm using to filter some EMG signals through electrodes. When I test it with multisim it works really well as you can see, but when I test it with real equipment (...
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84 views

Synthesizing this simple analog notch filter?

I want to synthesize this simple analog audio filter which is a notch: The inductor with resistor creates a simple one-pole low pass filter with the cutoff frequency at: fc = 1/(2pi L R) The ...
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73 views

Audio HPF cutoff frequency selection

I need to use a HPF for my headphone amp and I want some suggestions about at what frequency I should place the cutoff frequency. Currently I want to use a HPF with a fc=15~20Hz but this gives me -...
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57 views

What condition must be verified by the frequency so that an RC circuit acts as a differentiator? [closed]

So I am theoretically planning to make an RC differentiator circuit but I'm still a rookie with it so if someone can help me it would be appreciated.
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17 views

Should Passive LPF/HPF Component Selection Depend on Ability of Input to Source Current?

When choosing R and C for a passive LPF or HPF, should you take into account the input's ability to source current? I'm currently working on a passive HPF for an input that can supply up to 10 mA @ 3....
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28 views

Combine High and Low-pass filters to create 2-way crossover

I am in a bit of a dilemma. I was given 2 Bose tweeters (8ohm) and a Bose woofer (2ohm). They came with a build in amplifier which I want to get rid of as it makes the system unnecessarily large. I ...
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98 views

\$V_o/V_s\$ of given circuit

I'm trying to calculate $$\frac{V_o}{V_s}$$ of the given circuit, but don't really know what to do with the voltage dependent voltage source. As I'm not an engineering student, this stuff is very ...
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99 views

Need help in designing a BJT Amplifier with Avnl = 100

For our final project, we need to design a "single-stage BJT-based highpass amplifier using voltage divider configuration". The amplifier has the following requirements: \$V_{CC} = 12V, f_L =...
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65 views

RC filter for emitter follower input

Please could someone explain how to compute the impedance with which to determine the frequency characteristics of the high-pass input filter in the following circuit? My question is prompted by an ...
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1answer
306 views

Questions about the baxandall circuit

So I understand that the baxandall circuit is a tone control circuit, able to configure a bass and treble through RC filters. The general understanding I have from it, is that the capacitance of the ...
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53 views

How does a high pass filter and a low pass filter work for an amp?

I'm researching how to incorporate treble and bass into an amp. X1 is for bass, X2 is for treble and X3 is for volume. Intuitively, for me, if a high pass filter only allows frequency above a ...
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48 views

Second order RC filter and transfer function. Best method?

I need to analyze this filter and get the transfer function. I already did the job but I am asking you if there is a better method to solve this one ? (I heard of Facts method but I don't know how to ...
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3answers
560 views

Differential filters: high pass, low pass, band pass

I am looking to use a band pass filter in an EMG circuit design using the differential signals you receive from an op amp (differential/instrumentation). I have been looking for what is the proper way ...
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61 views

How to design a high pass filter given a stopband and cutoff frequency? [duplicate]

I have fs = 132 Hz and fc = 770 Hz I want to design a first order high pass filter that increases gain at a rate of 20dB per decade from 132 Hz until 770 Hz. Before 132 Hz the filter must stay ...
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94 views

How do I convert poles and zeros of a transfer function into a circuit / required circuit components?

I have been given a bode plot of a low pass filter, and tasked with essentially reversing the effects by using a high pass filter. I have solved for the transfer function which is the first equation, ...
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213 views

RC differentiator giving a higher output amplitude than input amplitude

This is the circuit: simulate this circuit – Schematic created using CircuitLab And this is the output: I am unable to understand the increase in output amplitude as compared to the input's ...
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1answer
165 views

Working principle of the AD8232 high pass filter

This is the datasheet of the AD8232. On page 22 in the section "Additional High-Pass Filtering Options" is this diagram: It is said that the cut off frequency is located at I tried to find out ...
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420 views

Why is the cutoff frequency of this highpass filter with formula different from LTspice?

I used this online tool to play around and design a Sallen-Key low pass filter with a cutoff frequency of 0.3Hz. When I now put the resulting values for R1, R2, C1 and C2 in the formula I get exactly ...
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196 views

High pass shunt filter

I have a DC motor, which is used as an electromagnetic brake. However I want to leave certain frequencies uninhibited, so I thought this should be possible by adding a shunt filter on the DC motor ...
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542 views

High pass filter for use in amplifier circuit

I've designed an amplifier for a small ac signal (amplitude of around 5mV, frequency 252kHz) with a BJT (2N2222.) The BJT is set up in a common emitter amplifier configuration, with the biasing ...
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106 views

Is the Roll-Off of Butterworth Filter of degree N always N*20db/dec?

I am trying to implement a fourth order Butterworth high pass filter under a Sallen-Key topology. Two frequencies, one at the passband and another for the stopband, are set to be at some specific gain/...
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123 views

Are my calculations wrong for the capacitance?

In an earlier post i discussed about the effects of voltage derating on a capacitor. From here i measured the output with DC and AC applied to a highpass filter and found the cutoff frequency with the ...
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112 views

How to generate this kind of filter?

I've been trying to understand this exercise proposed by my teacher. He asked us to find a combination of 2 ideal filters to generate a filter within the conditions of the image below. (That means, ...
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86 views

Amplifier and Low Pass filter not responding after few minutes of correct output?

I am trying to design an amplifier and low pass filter circuit for a piezo sensor. My frequency of interest is .3 Hz to 5 Hz, for first stage I have used charge amplifier and the subsequent 3 stages ...
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769 views

High pass filter for electret mic to mobile phone

I’m currently working on making a lavalier microphone for use with my phone and gopro camera. I know these types of microphones are readily available and can be purchased fairly cheap, but where would ...