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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18
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3answers
7k views

Understanding USB Inrush Current Requirements

In relation to a previous question, I'm trying to understand the USB 2.0 requirements for inrush current. I understand the basic idea, but a few details are still unclear to me. The specification ...
14
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2answers
2k views

How do you determine the effective resistance of a finite grid of resistors?

Disclaimer: I am a geophysicist with limited electrical engineering background. I am not sure if this problem is incredibly easy, incredibly complex, or completely nonsensical. My goal: Determine the ...
12
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5answers
26k views

RC differentiator circuit explaination

This is the circuit of a basic RC differentiator, with the input/output voltage waveforms. First of all, I don't understand why there is decrease in the output voltage (discharging of charge from ...
9
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4answers
2k views

The Intuition for RLC circuits

I'm reading through Hayt's Engineering Circuit Analysis 9e and it does a fairly good job of giving the intuition for "where" the energy is going in a damped RLC circuit, but I'm hoping that someone ...
8
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5answers
4k views

RC circuit understandings

I am trying to understand the principles of a RC charging / discharging circuit however I'm at loss regarding certain aspects of its operation. I have a square wave generator giving 0v to 5V levels ...
8
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1answer
311 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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6answers
2k views

What does the value of reactive power represent physically?

In my power engineering course, we were introduced to reactive power. I believe I understand what reactive power is in essence: there is energy transfer between the source and inductor/capacitor. This ...
7
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4answers
3k views

Intuitive explanation for filters

Can anyone provide an intuitive explanation for the filtering action of RC or LC circuits? I know the mathematical treatment involving reactances but I was wondering if that could be explained ...
7
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2answers
623 views

Why do R and C have to be small for differentiator circuit

I'm a beginner studying The Art of Electronics, and on page 25 they introduce the differentiator. Basic circuit like so: They give the complete equation: $$ I = C \frac{d}{dt}(V_{in} - V) = {V\over ...
7
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4answers
8k views

Calculate the value of an inductor using an RL or LC circuit

Given an inductor of an unknown (though magnitude-estimatable) value, and a resistor of precisely known resistance, how can one calculate the inductance of the inductor? Tools I have at my disposal: ...
7
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2answers
501 views

Filter Design Preparatory Book Recommendation [closed]

It is generally agreed that Zverev's "Handbook of Filter Design" is THE reference work for LC filter design. However, I crack it open, and the first thing he does is head off into lattice filter ...
6
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4answers
1k views

Why is a linear passive circuit stable, i.e. why does its impulse response approach zero over time?

This is a silly question to ask because the answer might be obvious, but I still have my doubts. If given a circuit composed only of resistors, inductors, and capacitors, if its impulse response ...
6
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3answers
2k views

Why would I use a transformer instead of one inductor in a crystal set?

I'm reading up on A Simple Radio Receiver. I have a question about this image: The signal from the antenna (perhaps a few tens of microvolts, or hundreds for a nearby transmitting station) is ...
6
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5answers
12k views

Circuit to remove noise from digital communication line

Carrying on further from my previous post and drilling down to specifics, I am trying to figure out the right way to implement "glitch remover", or "noise remover", using electronics (i.e. not in ...
6
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2answers
2k views

Calculating values for compensation network (boost converter RC+C network)

I'm trying to build a boost converter with current mode PWM control, but I'm stuck at selecting capacitor and resistor values for compensation. I'm using a LT1619 as the controller IC: simulate this ...
5
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3answers
2k views

Thevenin Equivalent Voltage: why ignore the 3-kΩ resistor?

In order to find the Thevenin voltage here, why is it that the 3k Οhm resistor is ignored and no current goes through it? (hence \$V_{TH}=8mA \cdot 7kΩ = 56V\$)
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5answers
2k 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 ...
5
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5answers
2k 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://...
5
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3answers
2k views

Recommendation for ADC noise filtering?

I'm using an ADC (adc081c021) with a pretty noisy input: There is also a 5-second video here: http://tinypic.com/player.php?v=2ue47cm&s=5 The objective is to detect the two peaks. How could I ...
5
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3answers
2k views

Impedance matching an RLC circuit (inductor macroscopically drawn on PCB)

Context: I am a physics grad student with basic knowledge of circuits, but impedance matching and RF domain are beyond my normal scope. My PCB is actually copper bonded to a ceramic substrate that is ...
5
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3answers
1k views

What does the impedance look like around a small resonant loop?

Say I have a hoop of conductor, broken at the top, with a capacitor across the gap. The inductance of the hoop and the capacitance form a series resonant LC circuit: Now, say this loop is excited by ...
5
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2answers
270 views

Why is this a 7th order circuit?

This is the circuit: I saw it in a book. It said that this is a 7th order circuit. From theory we know that the order of linear passive circuits is determined by the sum of capacitors and inductors, ...
5
votes
1answer
132 views

How does the second order time constant affect circuit behavior?

I learned that the transfer function of a second order circuit can be expressed in the following standard way: $$ \frac{K}{\tau_s^2 s^2 + 2 \zeta \tau_s s + 1} $$ Where: \$K\$ is the gain \$\zeta\$ ...
4
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2answers
2k views

LC Circuit problem!

Initially when the switch is closed ,at that instant the inductor is a short and capacitor is open ,so the diode cathode is floating ,so how does the diode conduct? Does the LC circuit resonate? My ...
4
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3answers
3k views

Why is series LC circuit not behaving as band pass filter?

I am trying to simulate LC circuit using external source that generates square wave of 503Hz of amplitude 2V as below: Natural frequency of circuit above is 503Hz.So it must pass this much ...
4
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1answer
1k views

Resonance of Parallel RLC circuit

For the circuit above, I was wondering how they derived the formula $$\omega_0 = \sqrt{\dfrac{1}{LC} - \Big(\dfrac{R}{L}\Big)^2}$$ If anyone is able to walk me through this it would be fantastic.
4
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3answers
836 views

Source-free, under-damped, parallel RLC with 2 intial conditions

I think I'm suffering from brain-drain. I'm trying to solve a 2nd order differential equation for the natural response of an under-damped parallel RLC circuit with initial conditions of \$I_L\$ and \$...
4
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2answers
10k views

How to design a 4th/6th/8th passive low pass filter?

I am trying to design a 4th/6th/8th passive low pass filter. The filter is used after a DAC to generate a fixed frequency sine wave. The DAC will export a square wave at 1kHz. So the pass band of the ...
4
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3answers
2k views

Damping in an RLC circuit

In an RLC circuit,what criteria could be used to decide whether the system is overdamped or underdamped? Could we compare the maximum energy stored during one cycle to the energy dissipated during one ...
4
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3answers
503 views

Why does my transistor circuit produce a wave?

Could some one explain to me how my circuit works? I accidentally hooked this up while trying to work out an amplifier. I'm thinking there's something like RC resonance going on, but I'm not sure. ...
4
votes
1answer
2k views

Hall effect sensor output type - open collector vs RC

I am about to select a hall effect sensor. Two types are available: one has an open collector (OC) output, the other an RC output. The datasheet states that both are current sinking. But because I ...
4
votes
1answer
140 views

Capacitors in parallel going negative

Interesting (maybe?) question here which I am struggling to answer. Hoping someone can help. I have a capacitor network; 5 caps in parallel and then two modules of that configuration connected in ...
4
votes
3answers
753 views

LC lowpass filter optimization

I have some 12 volt cooling fans which interfere with a radio transmitter. I notice that if I either put a large capacitor in parallel, or a large inductor in series, I can eliminate the noise heard ...
4
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1answer
2k views

Thevenin equivalent circuit with current and voltage source

I have the circuit below and I have to calculate complex current i1using thevenin equivalent circuit method: I tried to follow the rules and open the terminal <...
4
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1answer
237 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 = ...
4
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2answers
1k views

Change capacitance or resistance in RC circuit

When tuning an RC circuit you can choose either to tweak the resistance or the capacitance. I was wondering if there are any benefits for choosing one over the other depending on what you are trying ...
4
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0answers
208 views

Home made passive tablet pen

I have an old wacom tablet at home, its really big and I'd like to use it but I've lost the pen for it. It uses pens with passive LC circuitry. The board creats an EM-field (I can see it on my ...
3
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3answers
8k 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 ...
3
votes
3answers
13k views

Behavior of RLC circuit elements at t = 0

I'm wondering what are the behaviors of the inductor, L, and capacitor, C, at t = 0+ Please correct my understanding of the above circuit if I am wrong. At t = 0, the capacitor acts like a wire. So ...
3
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5answers
3k views

How to use input/output termination resistors in filters?

NOTICE: I have added another question here that a solution for each one may help for solving the other one. Please look at Fig-1 below. It is a common usage of termination resistors. R1 , R2 work ...
3
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3answers
3k views

RF transmitter circuit explanation

I just can't get my head around how these RF transmitters work: simulate this circuit – Schematic created using CircuitLab What I do know about them is the following, correct me if I am wrong. ...
3
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3answers
908 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?) ...
3
votes
1answer
877 views

PIC 16F84A RC oscillator problems

I'm trying to use an RC oscillator on a PIC 16F84A-20 that I have on a breadboard. The code is supposed to (at this point) simply flip an output back and forth every so often. I don't need it to run ...
3
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4answers
117 views

Equicalent circuit - RC // RC

I am doing a filter analysis of a simple network filter, requiring drawing some equivalent circuit to simplify the expression and analysis of the transfer function. The issue I've got is regarding a ...
3
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2answers
716 views

What are state space equations?

I'm in a Linear Circuits semester II class, and we're going over 2 port networks. State space equations show up on the practice exams but not the lecture slides or book. I was wondering if they were ...
3
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1answer
5k views

Oscillator for High Voltage Transformer: RLC or Blocking Oscillator

What type of oscillator is being used in the schematic? How is that particular oscillator working in this circuit? I'm less than confident with oscillator theory, and I can't tell if this is RLC or a ...
3
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2answers
1k views

Series RLC circuit problem

I have attached my attempt and the solution provided by my instructor. I am confused on 2 things what it means by "the circuit is in quiescent state" ? why is he getting sqrt(8) in the current ...
3
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2answers
2k views

RLC - Understanding Phase Shifts

I'm having trouble understanding intuitively phase shift for RLC circuits. For example, I have seen the following: In the low-frequency regime, which element is the dominating element (highest gain)...
3
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2answers
435 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 a ...
3
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3answers
6k views

Electric car “J1772” charger - “pilot” signal sequencing with passive circuitry

J1772 Some background: Many electric cars are designed to use a "J1772" charging point. The main signal in the J1772 specification is called the pilot. Long story short, the car is expected to ...

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