Use this tag for circuits that only contain passive components, such as resistors, capacitors, and inductors. This includes RC, RL, LC, and RLC circuits.

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Analysis of overdamped series RLC circuit (from “Foundations of Analog and Digital Circuits”)

I'm working my way through "Foundations of Analog and Digital Circuits (Agarwal)" and am, for the first time, stumped. Specifically, they analyze an over-damped, undriven series RLC circuit in ...
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57 views

Finding the resonating frequency

Here in the given figure is a parallel circuit. The goal is to find the resonating frequency (fo).How can we find out the resonating frequency in that case? The formula in the given link won't work i ...
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2answers
114 views

Is the output of this LC circuit a DC current?

On the left of the circuit shown below is a 120V AC current. I know that the diode (D1) rectifies the signal so that only the positive half of the AC signal goes through. I have seen circuits with ...
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1answer
29 views

Confusion with cut-off frequency calculation using Thevenin equivalent of an RC low pass filter

When I was trying to see the effect of load at the output of an RC low-pass filer I found myself in some sort of confusion. Below is an RC low-pass filter circuit with another R as a load and its ...
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647 views

Using a large resistor instead of a flyback diode

In a video lecture a professor is explaining how to prevent an electric arc caused by the switching operation in an RL circuit. Here is the section (at around 18:26) where he explains it: https://...
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80 views

Admittance inverter realisation in filter design

I read some theory about lowpass prototype filters in the "Handbook of Filter Synthesis" by Zverev and in "Microwave Filters for Communication Systems". I read these two because I want to understand ...
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3answers
54 views

Determining cut offs frequencies of band-pass filter

I have an RC network as follows: simulate this circuit – Schematic created using CircuitLab As far as I can tell, this has the transfer characteristic: $$ \begin{align} \frac{V_{out}}{...
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49 views

calculate the transfer Function H(w)

how do I get the transfer Function H(w) of the filter in the image ? Thanks
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68 views

Input and output impedance in RC circuits

As far as I learned, the rule of thumb for the ratio of output impdance to load(input impedance)is 1 to 10. Thevenin resistance(output resistance) Rth should be very small compred to the load ...
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37 views

Analyzing LC circuit with multiple inductors and capacitors

I have a problem understanding what's going on in a more complicated LC circuits with multiple inductors and capacitors simulate this circuit – Schematic created using CircuitLab with ...
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76 views

A question about reactive power through a capacitor in LTspice

Before posing the question I would like to write the assumption I make for the power concept in passive circuits. As far as I know the power dissipated in an RLC circuit is the active power which is ...
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45 views

Current at specific frequencies in a RLC circuit

Having been given a circuit, that has a resistance R of 4.0 Ω, an inductance L of 0.50 H, and a variable capacitance in series supplying a voltage V of 200 V at a frequency fr of 50 Hz, I have ...
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92 views

LC Filter Response

I've been trying to replicate the step response of an LC filter in LTSpice but so far I haven't been successful. simulate this circuit – Schematic created using CircuitLab That is the ...
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1answer
47 views

Using KCL/KVL to derive differential equation of a mixed RLC-ciruit

I have the following LTI sinusoidal circuit, and I am trying to derive its differential equation using KCL and/or KVL. I need this to derive the Power Factor as function of the components, so I can ...
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1answer
57 views

Differential equation mixed RLC-circuit, C parallel to RL

I am having trouble finding the differential equation of a mixed RLC-circuit, where C is parallel to RL. It is a steady-state sinusoidal AC circuit. I need it to determine the Power Factor explicitly ...
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2answers
50 views

Network Analysis problem

I am not able to get the concept of how to calculate the output voltage. What I did was- I assumed the network N as such- simulate this circuit – Schematic created using CircuitLab Now ...
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2answers
62 views

AC transient analysis for LR series circuit for a given AC source?

How can we formulate the current for an LR series circuit which has an AC sine source? The current formula must include both transient current and steady state current. So the i(t) function should ...
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2answers
33 views

Settling time for an LR circuit with an AC sine source

How can we mathematically relate the settling time for an LR circuit with an AC sine source? By settling time I mean the time taken for the circuit reaching to steady state from transient state. This ...
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1answer
60 views

Does the physical distance from electrolyc capacitor to inductor matter?

I am designing simple LC circuit (L=470uH, C=1000uF) for 12V / 12A (1 Ohm load): As you can see, I did do some soldering already (without too much or noob thinking). The capacitor and inductor ...
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1answer
30 views

Can I use barrier rectifier as a diode in bulk converter circuit?

I have this LC circuit which will work under 12V and quite high load (10-20A): The diode D1 must be a shottky diode but the only similar thing I have at the moment is actually 3-leg MBR3045CT ...
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3answers
521 views

Using LC filter instead of RC filter in mains powered circuits

Above is a dimmer circuit. In some of these circuits I see a toroid inductor together with a capacitor forming a low pass LC filter which is called choke filter. My questions are: Why is RL used ...
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3answers
57 views

Intuition for resonant, natural, and oscillatory frequencies of RLC circuits?

I can't seem to get these concepts straight. To start, what are the official definitions of each? My current understanding is that: \$ w_0 = \sqrt{\frac{1}{LC}} \$ is the natural (and resonant?) ...
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6answers
1k views

Measure temperature on a moving engine valve: transfer voltage and reading wireless?

I am an automotive engineer with very very little or almost zero electrical/electronics experience. I am working on logging real time temperature values on an engine exhaust valve and mounting a ...
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1answer
98 views

Alternatives to motorized variable capacitor?

I want to dynamically fine-tune the capacitor (about 100pF) of an RLC series resonant circuit, so as to keep it tuned despite variations of the coil's environment. Operating frequency is f = ...
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42 views

implementation different than simulation

I have to build the below series RLC circuit , and output its bode diagram using NI ELVIS Instrument Launcher. It is for a bandpass filter, so the output is taken across the resistor. Before ...
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2answers
51 views

Audio Mixer Passive Attenuator Circuit

I'm currently designing a digital audio mixer. One common thing found on audio mixers is a optional 20dB pad on the input. I've seen some attenuator circuits but all of them require you to know your ...
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42 views

parallel rlc voltage source

I am learning about circuits and I have some questions regarding circuit initial condition: - no initial energy stored before switch is closed - there is current at L1 at t = 0- I am wondering: ...
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Network Function of a Band-Pass Filter

So I've been trying to derive a the network function for a Band-Pass filter. I use voltage division to get a relation for the voltage output across the inductor. simulate this circuit – ...
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209 views

Operation of LC circuit in Frequency Modulation with simulation and linking it to the basic principle of frequency modulation [duplicate]

Can somebody help how message signal (words spoken near microphone) is modulated using LC circuit and how lc circuit oscillates at particular frequency by applying dc voltage. In the below circuit l1 ...
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1answer
46 views

Multiple characteristic frequencies determined by one capacitor

I'm trying to figure out how to construct a filter with the following constraints. If it isn't possible, this would also be acceptable, albeit disappointing (and I would hope for some kind of proof). ...
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5answers
535 views

Resonance frequency of an RLC circuit

simulate this circuit – Schematic created using CircuitLab Is it safe to consider the resonance frequency of a second order RLC circuit to be alway equal to 1/sqrt(LC) or the transfer ...
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272 views

Does this oscillator have a name?

I found this oscillator schematic and I hope to find more information about it.
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2answers
93 views

What is the pole frequency of a three-phase LC filter?

Suppose I have this configuration: Assume L1=L2=L3 and C1=C2=C3. What is the pole frequency of this filter? Edit: As mcmiln says, this is not identical to the question here: Cut Off Frequency in ...
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82 views

RC circuit with two capacitors

Figure out the Vout wave form of the following circuit: ( assume the name of the 9u capacitor to be C2 and not C1) Is there any way to intuitively plot the waveform by understanding the behavior of ...
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65 views

How do you block a signal with a tank circuit?

I have a signal generator outputting 60 hz AC. I've connected the output to a capacitor (922uf) and inductor (0.0076H) which are in parallel with each other creating a tank circuit. These two values ...
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49 views

Impedance of a circuit that contains a 2 port network

simulate this circuit – Schematic created using CircuitLab So, firstly, find the y parameters of a network ( says the assignment). Which I did. Now for the impedance I get the a parameters (for ...
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33 views

Noise figure of a passive network at a temperature different from room temperature

Given a passive network at room temperature, the noise figure is the ratio between the output noise power density pw and and the output noise power density due to the source pwS F = pw/pwS = 0.5*k*T/...
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51 views

How to find differential equation satisfied by \$u_{R_{equivalent}}\$, \$u_{L_{equivalent}}\$ or \$u_{C_{equivalent}}\$ in complicated RLC circuits?

When i'm given simple RLC circuits i know how to find the expression for each voltage, for example the expression of \$u_R\$ the voltage between the borns of the resistor \$R\$, or the expression of \$...
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16 views

T-axis scale of a solved ODE

When I was calculating the following netwerk: Where given was: R=5,L=1,C=4,V_C(t)=10,I_T(0)=-2,V_in(t)=20. So the ODE that we get was: $$ \begin{cases} 20\text{V}'_{C}(t)+\text{V}_{C}(t)+4\text{V}...
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89 views

LC Tank Tuner for Super Regenerative Radio

There seems to be very little literature to explain the practical construction of a radio and how a super regenerative circuit actually act as a selector, amplifier, how a antenna is actually to be ...
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70 views

Understanding Resonant Frequency in a Series RLC Circuit

After spending a couple of hours on the internet searching for answers I'm hoping Stack Exchange can help me. Recently, using simulation software, I used an oscilloscope to calculate the resonant ...
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1answer
55 views

Non-resonant RLC band-pass filter

To create a band-pass filter using an RLC-circuit, i drew the following circuit (assuming R is given as 120): The corresponding transfer function is $$ H(\mathrm{j}\,\omega)=\frac{120\, C\, \mathrm{...
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143 views

Measuring Q and Bandwidth of an RLC series circuit using Oscilloscope

I have a HNC Lab assignment coming up. As part of the prep for the lab work we have been given an RLC series circuit for which we had to calculate some values such as volt drop , Wn, Q and Bs, which I'...
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91 views

Second-order Band-Pass Filter Gain Confusion

If I derive the equation for a bandpass filter (in this case, critically damped) from the RLC transfer function, I get a different result than I would get otherwise by combining the transfer functions ...
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66 views

What is the back voltage generated by this inductor in this practice problem?

The circuit is in a steady state, and the switch is lifted at t=0. In (a), i calculated the current i and the voltage v at the instantaneous moment that the switch is lifted. The current is 2A and the ...
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2answers
83 views

time constant confusion of second order system

For first order systems, its easy to get the time constant by using thevenin concept. Suppose i have a second order system ,for example consider a two stage cascaded LOW PASS FILTER with identical ...
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96 views

In which of the LCR circuit the charge will decay faster?

Our instructor gave this problem. Cc << C. At time t = 0, the capacitor C has charge Q. In which circuit the charge Q will decay faster. Its answer is Charge Q decays faster in (A). ...
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364 views

What is the role of capacitor C3?

Here you can see the schematic of an LC oscillator. When I change the value of C3 it changes whether I have oscillations or not. For example if C3=10u there are not stable oscillations, and if C3=...
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64 views

In clamper circuit why RC>>T ? and why diode becomes reversed biased as capacitor becomes fully charged?

In clamper circuit why time constant is very very greater than time period of the signal i.e, RC>>T where R=resistance, c=capacitance, T=time period. why diode gets reversed biased as soon as the ...
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127 views

What does happen if the ratio of an ideal transformer is complex?

I have seen two solutions, both of then containing a paradox: Firstly, current and voltage ratio are inverse AND conjugate. In this first case, the two-port matrix is not symmetric (non-reciprocal). ...