# Questions tagged [passive-networks]

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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### Initial current

In the following circuit, would the initial current used for the S domain transformation be i(-0)=0 or i(+0)=7/4, assuming the switch closes at t=0, taking into account i(-0)=i(+0)? simulate this ...
113 views

### General statement about arbitrary two-port resistor networks

Suppose I have a resistor mesh that is acting as a two-port network. I'm feeding in $V_\text{IN}(t)$ and I'm reading out $V_\text{OUT}(t)$. Here's an example of a potential circuit: Is it true ...
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205 views

### Charge sharing in capacitors with switching pulses

I can solve the output voltage for the given circuit below as the clock pulses increase. To find a steady-state value, I found the output voltage till it remained constant (around five clock cycles). ...
114 views

### Find capacitance such that voltage and current are in phase

I just cannot solve this exercice, any help? This is what I have tried:
1 vote
48 views

### Designing bandpass filter for audio amplifier

I am a 3rd year engineering student currently working on a project where I need to basically make an ultrasensitive metal detector. Basically, I need to create an alternating magnetic field by ...
1 vote
175 views

### Synthesizing an impedance given by transfer function (poles/zeros) using a passive network

I would like to synthesize an arbitrary passive network based on a given transfer function (poles/zeros). The origin is the output impedance of a voltage regulator for which I want to find an ...
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### Current source in parallel with a short circuit

If a Dependent current source is placed in parallel with a short circuit, to solve our calculations would we assume that no current will flow through the dependent source and hence we remove it. For ...
43 views

### Creating equivalent impedance for given measured frequency response (that does not involve blind trial-and-error)

I have a measured frequency response and I would like to create an equivalent impedance model for it. I start with a parallel RLC and then add series R and series L to the elements. I blindly tune the ...
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### Magnitude and phase of parallel RLC with series resistor

I have been looking for a while for this issue, but unfortunately I am bit stuck on getting the magnitude as well as the phase of a RLC circuit with a series resistor, seen from V1 (see picture). ...
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1 vote
70 views

### What conditions can cause a PCB fuse to fail and act as a resistor?

Context: Tx circuit that shoots 24V pulses into a transformer to get 240V out of it. The purpose is to drive a piezoelectric transducer. The circuit itself has a fuse protecting it at the entrance (...
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### Which matrix index should be used when Y (admittance) is shown to compose a circuit segment mapped to an ABCD matrix? Y21? Other?

I would like to cascade a serial capacitor with a shunt inductor to form an L-match network by multipling two ABCD parameters and convert the result to S-parameters that represent the composite ...
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1 vote
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### RLC circuit equation

I want to make equation that describe relation between vi and vc. I did it like this. Is this right way?
1 vote
80 views

### What is up with this series/parallel calculation? Inverse Laplace looks strange

I'm trying to find an analytic solution for this circuit. If the cap is inverted (series resistor to ground) the solution is straightforward. In this case I ended up with a strange cos term that makes ...
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1 vote
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### Thevenin's theorem for Voltage divider bias

I am calculating the base current of transistor Q1. To simplify the circuit equations, I applied the Thevenin's theorem and converter V1 and R1, R2 into Vth and Rth as shown in the image. Vth= V1x(R2/...
104 views

### Is the resonant frequency as defined for a second order transfer function same as the frequency at resonance in a second order electrical circuit?

When I studied second order system and thus natural, damped and resonant frequency I wondered if the resonant frequency I find using the formula $w _ { r } = w _ { n } \sqrt { 1 - 2 D ^ { 2 } }$ ...
1 vote
90 views

### Modelling a single trace PCB?

I am trying to model a PCB trace as a R, L, C circuit. Assumption: My PCB has a a single trace running through it. Just giving input from one side and taking output from other. There is not even a GND ...
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### How do you derive an expression for the output voltage of a ladder network of N sections?

I am really stuck with a result from a circuit lecture slide. I understand how the thevenin equivalent circuit for this section shows the general result. But I am stuck on how to prove it generally ...
74 views

### State-Space Model of Resonant Circuit

I am trying to determine the state-space model of the circuit shown below. Also shown are the KH equations. Those equations I put in a Solver (Mathcad), however the result does not seem correct. For ...
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### Parallel RLC Circuit with DC voltage source input

I am new to LTSpice and I am trying to simulate an RLC parallel circuit with a DC source. The ideal switch is initially open and then closed at t=0+. The input is an ideal DC source with 1V. I have a ...
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328 views

### Question on RC circuit.(Texas Instruments interview)

I have confusion in this circuit. I know at t=0 both capacitor charges instantly. and voltage divided between both capacitors equally. but after some time output loop start active and capacitor C1 ...
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### I designing a pulse generation circuit using capacitor and resistor but my output is not coming as expected

I am designing a pulse circuit which I will be feeding to a comparator. I am using a combination of resistor capacitor and diode for generating positive edge triggered pulse as shown in the below ...
60 views

### Which of the following is LC lossless function?

Which of the following is LC lossless function and why? Pick one of the valid LC lossless functions and realize it using Foster-I and Cauer-I form. I have been trying to solve this question for ...
71 views

### Confusion with determining lossless function

Why is not a valid lossless function? Below condition 1, 2, 7 or 8 constitute the sufficient conditions for being a lossless function, but I am confused why is this not a valid lossless function. ...
1 vote
63 views

### Differential equation of a LC circuit in series with a parallel RLC circuit

I have the following RLC circuit. I am having trouble finding an expression for the natural response of this circuit. I found a similar question, but I was unable to simplify exactly like was done in ...
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### How is energy conserved in an LC tank with voltage offset?

Consider an ideal LC tank oscillator offset by an ideal battery*: The core question is this: is the energy balance here maintained by the charge-voltage relationship of the battery? Energy seems to ...
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54 views

### How to simplify matching network LC circuit

I'm relatively new to RF design, and trying to implement a Micrel reference PCB antenna design (Heli-2). I am using a MICRF113 RF transmitter at 315MHz to transmit digital data using ASK (OOK). Here ...
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### Capacitor current in parallel network with ESR and parallel resistance

So this might be a very simple question and I've got a knot in my brain but I've been at this for days and don't see how I could solve this problem. I'm trying to find the solution for both ucA, ucB(t)...
66 views

### Differential stripline characteristic impedance measurement

How would you measure the characteristic impedance of a differential pair (stripline) if you don't have access to a Vector Network analyzer? I have access to an oscilloscope and a signal generator. ...
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1 vote
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### Laplace Transformation: Determine the current through the inductor versus time i(t)

simulate this circuit – Schematic created using CircuitLab I am trying to find the current through the inductor versus time i(t) using Laplace transform. Converting everything into the s-domain: ...
51 views

### Phase of grid current is not varying in the simple RL circuit

I am trying to implement the following circuit: Circuit parameters are as follows: R1 = 2 ohms L1 = 10mH V_inverter = 28.175V (peak) V_grid = 200V (peak) I want the grid current to vary in full ...
1 vote
114 views

### How would you find the quality factor of this RLC circuit?

I have been trying to find the quality factor of this RLC circuit for some time now. My method is trying to find the equivalent series RLC circuit and calculate the resonant circuit. When I work ...
124 views

### LT Spice: parallel RLC circuit resonator giving weird frequency response?

I am trying out the following parallel RLC circuit configuration: On trying out other similar parallel circuits (like with an RL coil in parallel with C or with RC and RL branches in parallel) I got ...
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### How to find nature of RLC circuit?

If a resistance value, XL value and XC value are given, how do we determine the nature of the circuit (whether it's capacitive, resistive or inductive)? The only thing that comes to my mind looking at ...
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### On the topic of Quality factor in arbitrary RLC resonance circuits

In question Quality factor in arbitrary RLC resonance circuits, the OP asks about the Q of more complex circuits other than simple series or parallel RLC topologies. The responses I read, in ...
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### How to determine the time constant from an RL circuit graph?

I have an RL circuıt and this is the RL circuit's input and output graph. How can I fınd the time constant in the graph using the cursor?
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### RLC circuit as an average filter

I have simulated a buck converter in LTSPICE, and below is the switching signal (red )that goes into an RLC filter( vout as green). The filter does not average the switching pulses, So I believe the ...
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### Measuring inductor current with oscilloscope in a parallel RLC circuit

How can I obtain the inductor current waveform on the oscilloscope? If L=1 henry then integral of voltage across the inductor can give me the current but if the oscilloscope can't take the integral ...
1 vote
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### MC34063 inductor current peak does not match calculations

I am trying to design a voltage inverter based on old/cheap/jelly bean parts. I wanted to use the MC34063. Mostly for learning purposes, so I don't look for easier parts to use for now. I run the ...
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1 vote
158 views

### Damping Ratio Implications for an Increasing Resistance In an RLC Circuit

I have managed to derive the 2nd order ODE for a simple RLC circuit (this circuit is part of a booster dc-dc converter). I derived an expression for the damping ratio of the circuit and fact checked ...
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### The circuit modeling a surge test [closed]

In the surge test as far as I know, a capacitor is charged to a high voltage and is discharged via an RL load. The voltage is a decaying sinusoidal across the capacitor. This is the general picture I ...
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### RLC bandpass filter transfer function

I've been tasked with finding the transfer function of the RLC filter shown below. I converted to the S-domain and used the voltage divider rule to find the output, and came up with: H(s) = \frac{R}{...
119 views

### Making a DC to AC converter at home

My idea was to build a DC to AC converter, and I want to make sure it's feasible: simulate this circuit – Schematic created using CircuitLab A supercapacitor has very low voltage operating ...
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### Finding the current through an inductor in a second order circuit?

Assume that the circuit has reached a steady state. I'm trying to find the current through the inductor at some time, t, which should be a function of t. I'm having trouble creating a system of ...
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### If all the resistances inside a passive resistive network is multiplied by some factor, what will happen to the thevenin resistance?

Lets imagine an arbitrary passive resistive network, a black box. Let its Thevenin equivalent resistance across some terminals $a,b$ of the network be $R_{th}$ ohms. Now lets imagine another ...
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