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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21 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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41 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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56 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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43 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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38 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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150 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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80 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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66 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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55 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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16 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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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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60 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 = 300 Hz, ...
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30 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
90 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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37 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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46 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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133 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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57 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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80 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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177 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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132 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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203 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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133 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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333 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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72 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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111 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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108 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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77 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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425 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 ...
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1k views

Differential Equation of a First Order High Pass Filter

I am just stumped right now b/c I do not know how to write the "differential equation that describes this system. I did learn to write equations with impedances but I believe this is not what this ...
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161 views

X5R capacitor derating and highpass filters

X5R capacitors derate to about roughly 85% when DC voltage is applied, from what I have been told. Does this have an effect on high pass filters, even though HF filters off DC (0Hz)? If I wanted to ...
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348 views

Using capacitors for ethernet isolation? [duplicate]

The standard for ethernet says you should use a transformer for isolation. It seems like a cap-based solution would be smaller, more versatile, and a better fit for my application. Is there any ...
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141 views

How can one of the RC networks of this active high pass filter topology work as an actual high pass filter?

I have seen some previous vague questions related to a similar case but not for this topology. The following circuit (source: http://stompville.co.uk/?p=470) shows an alternative topology for an ...
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994 views

How to calculate the transfer function?

I have The following circuit network (link to multisim) and i am asked to find the transfer function, the max and min value, the cutoff frequency, angle and the type of the filter. [the actual ...
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1answer
64 views

Designing a Band Pass Filter

I need a band pass filter that only accepts frequencies from 1000 to 1400 Hz and then toggles the transistor. It has to work from .1 Vpp to 1 Vpp and rejects anything else. I have been testing this ...
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489 views

Bode Phase Plot of RC High-Pass Filter

I have been trying to understand Bode Phase Plot of RC High pass filter. I know that from my engineering that voltage lags behind the current passing through the ...
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523 views

High Pass Filter Design from Transfer Function

I need to design a circuit that implements the following transfer function: \$G(s)= G\frac{s+z}{s+p}\$ where, G = gain, p = pole and z = zero.
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271 views

change level of positive square wave signal to negative

A general question: Lets say I have a square wave signal from 0 to 5 volts. What I would like to do is create a circuit that will convert this 0 to 5-volt signal to a -2.5V to +2.5V for example. ( ...
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68 views

What's this amplifier filter configuration?

I've come across an audio amplifier circuit that contains this following configuration: I recognize R1,C1, and R3 to be part of a first order high pass filter, but I'm not sure what C2 and R2 are for....
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2k views

High Pass vs Low Pass simple Circuit (RC vs CR)

In an RC circuit, where the resistor comes before the capacitor, the circuit acts like a low pass filter. Whereas in a CR (I don't know if that is how you say it) circuit, where the capacitor comes ...
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157 views

How ac coupling in scopes does not give you a phase shift? Or does it?

For what i know, filtering something always gives some amount of phase shift. So how do oscilloscopes with ac coupling don't have that? Do they correct in software? If so, how they used to do it at ...
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138 views

Negative Voltage Shift from Blocking Cap for Amplifier

Recently I have been working with the Analog Devices AD797 op-amp in LTspice, and have been getting poor performance from the amplifier when using a low-amplitude signal. This is my circuit in LTspice:...
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104 views

By replacing capacitor values with different ones in a circuit, will the circuit still work? [closed]

I'm fairly new to electronics and following this schematic for a "Truth Meter", which detects sweat from your fingertips and a lights up an LED depending on the resistance of the skin, as one of my ...
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96 views

Physical significance of positive group delay with negative phase delay

This question is an addendum to: Is group delay the same as the delay of a certain frequency? Lately, I've been going back to basics to better understand the concepts of group and phase delay, so I ...
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53 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,...
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324 views

How to calculate cut-off frequency for T section high pass filter?

This is a high pass T filter: According to me, if input voltage is \$V_{\text{in}}\$, then voltage across the inductor \$L\$ should be $$V_x=\frac{j\omega L}{j\omega L + \frac{1}{2j\omega C}}V_{\...
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82 views

RL filter output attenuation

I am designing high pass RL filter. R is 550 [Ohm], L is 220 [uH]. I calculated that time constant is therefore 0.0000004 [s] and -3 dB pulsation 2 500 000 and frequency 397 887 [Hz]. I put this on ...
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2answers
77 views

Understanding Working of High-Pass RC Filter

I was trying to visualize what happens when frequency is swept from 1Hz to 1GHz. In case of capacitor, voltage lags behind current by 90 degree and capacitor reactance depends upon it's frequency. I ...
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1answer
102 views

The Art of Electronics 1.35

Forgive me if this is not the proper question format. Please critique it if not. I am new to this site. I am reading "The Art of Electronics" and cannot understand the jump made in equation 1.35 to ...