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Questions tagged [circuit-analysis]

Circuit (Network) analysis is the process of finding the voltages across, and the currents through, every component in the network.

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Op-amp problem, two inverting amplifiers?

So I stumbled across a rather strange ideal op-amp circuit that I've never encountered before. I've done enough problems regarding inverting amplifiers, non-inverting, summing, difference, and such, ...
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34 views

How to find voltage across resistors in RC Circuit with 2 voltage sources?

I've been struggling with this difficult RC circuit that asks for the voltage, Vo, across the R4 resistor. Edit: Assume that the switch has been opened for a long time, before it is closed at time t ...
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75 views

How to decide on the values of a set of resistors for a circuit?

Say i have a PN2222 transistor that i want to integrate into a circuit to amplify a signal with a gain of 100 or so. From the datasheet of the transistor i can determine that ...
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114 views

Finding total energy for RC discharged capacitor at t = ∞?

Most Rc circuits are not as severely difficult as this kind of circuit. I'm trying to solve for both the time constant and the voltage V2 across the R2 resistor, both of which will hold the necessary ...
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103 views

RL Circuit Analysis with 2 sources, how to find current of resistor?

I've been tackling some problems related to natural and step responses for RL & RC circuits, but I think I've hit a major roadblock for this RL circuit. I'm trying to find the time constant and ...
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24 views

Can a dependent voltage/current source have some impedence/admittance,respectively?

Im studying 2-port networks, for Z parameters equations, there is general equivalent circuit given, in which dependent voltage source is given, I do know about dependent voltage sources, but do these ...
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Derivation of \$Z_{och}\$ & \$ Z_{sch} \$ for a symmetrical lattice two port network

I've been trying to proof the open circuit impedance of half circuit [i.e \$Z_{och}\$ ] and short circuit impedance of half circuit [i.e \$Z_{sch}\$ ] of symmetric lattice two port network (which is ...
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94 views

Power absorbed by load resistor

Can someone double-check where's the mistake? The system didn't accept my answer. TASK: Find the maximum power absorbed by the load resistor, knowing that: $$E = 6.6V; R_{1} = 12.1Ω; R_{2} = 14Ω; R_{...
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36 views

Current pulsing circuit, troubleshooting

I was not sure what to title this question. What I have two version of the following circuit, that I have built and modelled. The application is to create a pulsed magnetic field, by pulsing a ...
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1answer
26 views

NTE 4050 buffer and current sourcing capability, datasheet reading woes

I am trying to construct an output that is switched on by the inputs to a buffer. The buffer input, in the final design, will be sourced from an Arduino or Raspberry PI. I needed the buffer because ...
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33 views

RC circuit with pulse input voltage; finding the time constants

I've the following circuit: Question: What are the time constants of the voltage at node \$\text{Y}_2\$ when the up part of the puls comes and when the down part of the puls comes? MY WORK: The ...
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33 views

Finding indication of ideal ammeter

Would anyone share some tips, advices for solving this task? So far, I have dealt with far simplier electric circuit's tasks. This is new to me. Any kind of help or advices are appreciated, thanks!
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61 views

Difference between ideal and practical ammeter?

What is the difference between the ideal and practical ammeter? To be more precise, here's my task: I do not need a solution to this. Just looking for a clear explanation between practical and ...
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52 views

Why the mosfet's gate resistor show this current consumption?

Here is my H-bridge circuit. and here is the graph of the current of R1, with LTSpice My calculation for the bases of the pnp & npn Vsupply -((Vbase Q3 - Vbe) / R5) x R3) 24V -(((3V3 - 0.65)/...
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37 views

WPT compensation topologies

I'm experimenting with compensation topologies for inductive WPT systems and have a small confusion. The general WPT industry uses compensation networks to cancel out reactive components in the ...
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101 views

Finding Thevenin Resistance Amp Op

Hello folks, I've got some douts about how can finding the \$R_{th}\$ seen between \$V_{out}\$: A: is a amplifier gain The possible answer are: A) \$ R_{th} = (A.R_s)\$ B) \$ R_{th} = (R_s + A)\$ ...
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57 views

How to calculate current from a phasor?

I'm just working through some textbook exercises and have been stuck on this one for a while. The question is: The current in an AC circuit is represented by the phasor \$I = I_0 e^{j(120\pi t + \pi/...
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94 views

What is the purpose of extra parallel resistor R2

This probably is a very basic question. I looked at a real world device schematic - a "digital pushbutton" and can't figure out why R2 is necessary. This device is supposed to be connected to arduino....
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26 views

Virtual SPDT with half-bridge and op-amp comparator

I have the following circuit composed of an op-amp comparator and a mosfet half-bridge: I would like to "confirm" the following: if VBUS is floating, nothing will happen. Especially, there will be ...
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2answers
56 views

Combining perfect voltage and current sources

I am attempting to reduce the circuit shown into a form of a single voltage source and resistance in series using Thevenin and Norton conversions. I approached the problem by first considering a ...
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2answers
73 views

Analysing circuit for digital filter design

I have a hard time understanding how one would come up with \$H(j\omega )\$ given a circuit for an unknown filter. The circuit looks like this: I know that: \$H(j\omega ) = \frac{Y(j\omega )}{X(j\...
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33 views

Network Analysis for finding power delivered

We need to find the power delivered by the 5V source in the above network. I usually apply superposition theorem when I need to find the power delivered by a source when there are many power sources ...
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47 views

Crystal Oscillator Power

In the following circuit: taken from: https://circuitdigest.com/tutorial/quartz-crystal-oscillator How is the crystal powered to begin oscillation? I understand the amplifier is required to prevent ...
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63 views

Problem in understanding notations and symbols

I have been reading the book Leon, Desoer and Kuh and I am facing some difficulty in understanding the notations. In the above pictures, I am not able to understand what equation 1.7a wants to ...
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38 views

Nodal analysis; am I doing it correctly?

Here is the circuit: In the following, switch S has been open for long. No initial energy. C = 10 uF. R0 = 24 Ω R1 = 12 Ω R2 = 18 Ω R3 = 6 Ω Power Pr3 dissipated in R3 is ...
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30 views

Why does AC/Sweep in Cadence always require a starting and stopping frequency?

It seems as if there is no way to simply test a circuit with an AC voltage source at a single frequency. How does someone test a circuit that plugs into the main voltage at 60Hz? Is it really ...
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29 views

circuit test is performed on low voltage side ,and reading are given of high voltage side

There is a question in vk mehta in which open circuit test is performed on low voltage side ,and reading are given. of high voltage side and magnetizing branch ,excitation branch current is asked.how ...
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214 views

Gilbert cell. Understanding the basic

I am trying to understand a concept of Gilbert cell. I have the next figure. Quastion1: If +1V is set up in (3), then in (4) is admitted -1V, and for (5) is -1V, (5) +1V. The current source is sume ...
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49 views

Calculate the capacitor voltage for t < 0 and t > 0 for the circuit below

Please help me calculate this. I tried using the thevenin equivalence method however I'm not familiar with two independent sources in a circuit. When I was simplifying using thevenin method the ...
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2answers
77 views

Confusion about Laplace and frequency response of a electrical circuit

I have a confusion between the Laplace transform of a circuit and the frequency domain AC analysis. Suppose we have a series RLC resonant circuit connected to an ideal sinusoidal voltage source. We ...
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1answer
61 views

How to find the transfer function F(w) for this circuit? [duplicate]

Hi, My book on analogue circuits has this question and I have been stuck at it for the past three days or so. I am supposed to figure out the transfer function for the network as well as the cutoff ...
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65 views

Input resistance confusion

Here's a circuit of an amplifier in the CB configuration: The small-signal equivalent is (using hybrid-pi model) I want to calculate the input resistance \$R_{in}\$. If I'm not mistaken, the blue ...
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102 views

Why would we want a negative voltage as an output

In the problem, I solved that the transfer function $$H(s) = \frac{V_{out}}{V_{in}} = -\frac{Z_f}{Z_i} $$ My professor told me that the op-amp circuit allows for a transfer function whose voltage ...
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1answer
35 views

Input offset voltage for microphone circuit

Does anyone know what's the input offset voltage (oscillated 2.5V) to the op-amp in the circuit for? From my understanding, the input offset voltage needs to be extremely small so that output DC ...
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3answers
111 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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43 views

MOC3021 optocoupler not working ( or not working , a bit confused )

My Understanding As far as my understanding of MOC3021 optocoupler goes, it should latch pins 4 and 6 whenever there's a current flow between pins 1 and 3. The Confusion Image 1 - D1 not glowing ...
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90 views

741 Op. Amp.: Inverting input connected to output (pin 2 connected to pin 6). What does it mean?

simulate this circuit – Schematic created using CircuitLab I am a newbie electronics students. My question is, what does it mean (what happens) when you connect pin 2 to pin 6 on a 741 op. ...
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63 views

Best way to monitor on/off state with a microcontroller

I have 3D printer with a cooling fan that by design is on constantly, however it only needs to be on when there is something to cool! I have no idea why they have it on all the time since it is loud ...
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41 views

Rising edge duration of a low to high pulse

In a device I am using, I see the following in the description... "At start-up, the module requires an ON_OFF pulse sent from the host. A second pulse sent from the host will re-enter hibernate mode. ...
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74 views

Q: How to remove DC offset

simulate this circuit – Schematic created using CircuitLab Essentially my goal is to measure Node A and feed Node C into the arduino for further measuring. What I attempted was use a buffer ...
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2answers
43 views

Derivation of time constant for single source, single capacitor RC circuit

Take a circuit comprised of resistors, a single capacitor, and a single step response voltage source. Then: Every single voltage and current in the circuit, except at the voltage source, will have a *...
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77 views

ESD strike breaks the LAN8742A ethernet phy

My circuit uses LAN8742A ethernet phy. The system has a metal case and gets 220V AC to power supply board. After converting 5V DC it goes to my board that has Ethernet and mcu. I screwed case and ...
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122 views

Zero crossing detection circuit correct?

I am working on a DIY AC dimmer circuit with arduino. This project is part of the AC dimmer circuit as mentioned here Since, I was stuck in so thought of retracing my steps and checking each part of ...
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40 views

Parallel MOSFET Circuit Analysis

I'm solving part b of this question I started with the assumption that both MOSFETs were in saturation mode to simplify calculations, I then solved for the circuit, tested the assumption using vds, ...
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What are the limiting factors of these op-amps?

I designed a multiple feedback band pass filter ...
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1answer
48 views

Does anyone know how the Boss Metalzone sweepable mids affect the bandpass?

https://electricdruid.net/boss-mt-2-metal-zone-pedal-analysis/ http://sound.whsites.net/project150.htm Like in the original question - I'm struggling to understand the relationship between the op-amp ...
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2answers
39 views

Does anyone know how the low tone control of the Boss Metalzone works?

https://electricdruid.net/boss-mt-2-metal-zone-pedal-analysis/ http://sound.whsites.net/articles/gyrator-filters.htm#s9 I have been using these websites to try and work out how the eq works, but I'...
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72 views

Conceptual paradox with resistance in loop/node analysis

There are loop/mesh analysis and node analysis corresponding to Kirchhoff’s voltage law (KVL) and Kirchhoff’s current law (KCL), respectively. Let's consider three elements, R,L,C, connected ...
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34 views

Loop v.s. nodal analysis of periodic circuit network

I vaguely know there are basically the loop/mesh analysis and the nodal analysis corresponding to Kirchhoff’s voltage law and Kirchhoff’s current law, respectively. And one can do Fourier transform of ...
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51 views

Time Constant of a Complex RC Circuit

I'm trying to model a diode as two capacitances, a conductance, and a series resistance, as shown here: In order to generate an expression for the capacitance I'm equating 1/w3db to the time constant ...