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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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If we have four grounded nodes in a circuit, can we connect two of them together and forget that those two were grounds?

Refer to the image attached. I personally think the answer is no because it is not necessary for the currents through both the grounded capacitors to be the same in the upper circuit, but that is not ...
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407 views

Finding the Transfer Function of Spring Mass Damper System

I have been going through Ogata Modern Control Engineering book and working through several exercises to improve my understanding of basic control principles. I came across the following example which ...
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i don't understand the KVL solution to this question?

this is part of the solution of a previous exam and there are some things i don't understand about it 1- why did he assume the value of current at the 12 Ohm resistor to be 0.5A without any ...
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Finding necessary voltage for diode conduction

simulate this circuit – Schematic created using CircuitLab In the following, I need to find \$V_a(v_{in})\$ such that \$D_3\$ is on. Assume a forward voltage drop of \$0.7V\$. From past ...
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Solution of Linear Electrical Circuit

We learned in class that the number of independent KCL equations is N-1(N-number of nodes) and the number of independent KVL equations is B-(N-1) (B- number of branches). Thus we have B independent ...
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43 views

Flow of electrons

I feel like this is an extremely stupid question, but I am not from electronics! In diagrams, they use conventional current. If I were to make this circuit in real life connecting battery + with diode ...
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70 views

How to measure collector current in BJT?

In the following circuit: I know the expression for the collector current is $$I_C =\frac{V_{CC}-V_C}{R_L}$$ Say I have a potentiometer for \$R_L\$ and I decide to set it to 0 Ω. What would \$I_C\$ ...
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37 views

Does a discharging capacitor in an AC circuit add additional voltage to circuit?

In an RC circuit with an ac voltage source, after the capacitor becomes charged and then the sign of the ac voltage flips, does the discharging capacitor add additional voltage to the circuit compared ...
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How to calculate the voltage gain in this picture?

simulate this circuit – Schematic created using CircuitLab I know that by using \$A_v=-G_mR_{out}\$, and \$G_m=\frac{I_{out}}{V_{in}}\$, we can get the voltage gain of this circuit. After the ...
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114 views

How do I determine the purpose of this op-amp circuit?

I have this circuit and I was asked to determine V2=f(V1) and V3=f(V2) which I determined below. The next step is to figure out what the purpose of this circuit is but I'm not sure how to do it from ...
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29 views

Removing/Subtracting Lead Resistance Using Op Amp Circuit

I'm working with RTD sensor, and need to use Op Amp circuitry. Can someone explain to me how this Op Amp circuit work to remove the lead resistance? So that Rw1, Rw2, and Rw3 vanish, hence the ...
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Vo in an RLC circuit

So I have this RLC circuit: And its equations for voltage addition, current conservation, ohm's law and a solution of those equations (Vo). Then there's this RLC circuit: With another set of new ...
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639 views

Understanding charge and discharge of a capacitor

I feel bad at this point. This will be my last post about it, however, I will explain myself more clearly and more transparent so everyone doesn't need to guess my issues. Never been so confused ...
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Q: Finding the current through the capacitor

Having a hard time trying to find the current through the capacitor I don't know what method to use. simulate this circuit – Schematic created using CircuitLab This is how far I have gotten: ...
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3answers
68 views

Moving Ground in between resistors in series

What happens when you move Ground to the given point? How does it affect the Voltage and the Resistors after moving it in the circuit? Missing values: .Current (I)= 30mA (V.R1)= 15V (V.R2)= 3.6V ...
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DC Black Box and Thenevin Equivalence

There's a DC Black Box, and my goal is find the Thevenin resistance within the black box. By connecting a digital mulitmeter to the terminal, I have found that the "open-circuit" output is \$0.647\ \...
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How does one do nodal analysis on this circuit?

I am having troubles trying to figured out the analysis of this circuit. simulate this circuit – Schematic created using CircuitLab Here's my attempt on trying to do nodal analysis on the ...
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60 views

Two capacitors of same value connected in series and connected to power supply instead of one capacitor of equivalent value for PCB design

what's the purpose of two capacitors of same value connected in series and connected to power supply instead of one capacitor of equivalent value for PCB design especially for Automotive applications
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How do I go about solving this and finding the value of v(t)?

I'm very sorry if the solution turns out to be very basic, but I'm a very recent student and my teacher is less than happy to help. edit: sorry for not posting my attempted solutions first. Here is ...
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Does a diode block current but not voltage?

When running this test circuit on CircuitLab and my expected result was that only M1 would open but then i noticed that the M4 mosfet is also open even though there is a diode between it and the the ...
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1answer
78 views

Basic Ideal Op Amp Circuit Analysis

I am trying to familiarize myself with operational amplifiers by going through this book by Sergio Franco. This is a basic question regarding the example given on page 16, which I am struggling to ...
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1answer
60 views

Node analysis in which branch contains Voltage Source

I'm experiencing problem while solving the circuit problem and finding Iab: It is because there is a voltage source on the branch which is connected to the left ...
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3answers
95 views

Need help explaining behaviour of a circuit

just can't wrap my head around this one for some reason. I am sorry if it's easy for you to see. Just confused on the duality of things in circuits, Is it a filter? Or is it a peak detector? How do ...
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66 views

Is there current flowing out of an Operational Amplifier output?

I came across the following self-study problem, taken from The Analysis and Design of Linear Circuits (8th edition). I was not intending to solve the problem, since I am just looking over all ...
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3answers
110 views

Differential to single ended audio signal

I'm working on an interface that will be connected instead of a speaker, input of my interface is differential, and output is single ended. I'm using the following schematics : R3 is the load to ...
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9answers
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If a circuit only has a current source and no voltage source where does the voltage come from to supply the circuit?

For example this circuit, A current source is something with would alter the voltage across it to meet a certain current. But where is there a voltage source to do this or even have a voltage at Vx. ...
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114 views

Explanation of this drawing (transistors) [closed]

I am very new to ECE and when i googled circuits for the beginner and this was one of them. So far i have a basic knowledge of transistors and that they exist. please correct me if i am wrong. ...
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91 views

Have i understood voltage correctly?

I am not from an engineering background, so this may be very simple and stupid but: Voltage is the difference in electric potential between 2 points Voltage drop describes the reduction in energy of ...
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1answer
54 views

NPN BJT Transistor Circuit Analysis Problem: Is This Question Solvable?

I've been doing some circuit analysis questions as practice but came across one that seemed very odd: As far as I can tell, this question is missing information and therefore unsolvable? I was able ...
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2answers
70 views

KCL / KVL Circuit Analysis

I have a question regarding using KCL / KVL to analyse the circuit below to find all currents and voltages. My question is : When performing KCL at the top centered node, what way should I assume ...
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2answers
58 views

Collisions of Thermal Impedances

As shown in the picture below, thermal impedances of an IGBT device depends on the temperature. However, there is a strange phenomenon as follows. While with increasing the temperature, steady-state ...
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1answer
36 views

How to calculate the zero input response of the current through an inductor?

The question is find the current through the inductor when the iL(0-)=.5A. The top picture is the posted solution. My solution is on the bottom. They are not the same and I realize that I should not ...
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1answer
66 views

How to find the output impedance of a two BJT small signal circuit?

Like for instance, the picture above. How to find the output impedance? My thought was like draw the small signal circuit of them, then do the equivalent. But I am not sure if I need to short the ...
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1answer
42 views

Writing the Nodal and Mesh equations for large circuit and large supermesh

Here's my circuit: simulate this circuit – Schematic created using CircuitLab I have defined the node 'voltages' and the mesh current directions and the currents themselves. What I want to do ...
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1answer
112 views

Confused about KVL / KCL / ohm's law

I am confused about when to use KVL/KCL or ohm's law to solve the circuit question? I need to compute voltage in point B and point C, every current pass through R1 R2 R3 R4 R1= 100 ohm, R2=300 ...
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1answer
50 views

combinational circuit interference

Hi I'm a complete newbie in EE, sorry if my question sounds dumb: Let's say there is a combinational circuit with one input and one output. And it takes 1 second to generate one output. If we put the ...
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232 views

Identifying an unknown code “W62” SOT363 dual inverter

QUESTION: What is this component? RESOLUTION: Equivalent part is SN74LVC2GU04DCKT normally code "CDK" This appears to be specially "Wacom" branded for obscurity. Question below for historical context. ...
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Sedra and Smith - Common Mode Input Resistance

So in Sedra and Smith, it is stated that the common mode input resistance of a differential amplifier is from the diagram(s) So it is stated in the book they have used the diagram on the right (...
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3answers
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How to find a number a such that an input 10e^-at to a transfer function does not have a Ke^-(at) term in the output

I have a transfer function, \$H(s) = \frac{-16(s+4)(s-1) }{ (s^2+16)(s+2)}\$. The impulse response is \$-16*(-3/10 * e^{-2t} + \frac{13}{10} cos(4t) + \frac{1}{10}sin(4t))u(t)\$. I am supposed to ...
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108 views

Howcome there is current flowing through the gate of this transistor?

I have a few conceptual questions: If there wasn't Rg (Resistor between gate and drain), would Vin = Vout then? For small signal analysis, current can flow through the gate (AC) if there's a voltage ...
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3answers
69 views

Integrator (Op amp) Simulation OrCAD

I'm working on in a integrator op amp and actually i make the desing in a breadboard and is working but in time of simulation is like there is not voltage in the output of the op amp. I don't ...
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1answer
29 views

Where might the fault be in this battery checker circuit from an old camera? [closed]

I'm repairing an old rangefinder camera, a Canonet QL17 GIII. I have had to do a lot of internal rewiring. All is now working, except for the battery checker functionality. I've included that part of ...
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2answers
86 views

Combining two ideal voltage sources with an impedance between them

Solving a problem, I came across the following source transformation:        My question is: I know that I can do the following:       &...
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2answers
70 views

Calculating Thevenin voltage and Norton current for complicated circuit

I asked this question before in relation to calculating power before but it seems I might have not been clear enough. I'll draw the original circuit and then the circuits for calculating Thevenin and ...
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1answer
67 views

Source transformation with impedance being inductor or capacitor

I found a presentation that states the following about source transformation when the impedance is capacitive/inductive: While electrical circuits books, like Nilsson's, says: If I transform the ...
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1answer
105 views

Differentiator (Op amp) with a square wave

I'm working on a differentiator (op amp) with a unitary gain i calculated the value of RC and the period with a frequency of (1kHz). Figure 1. Differentiator Schematic (OrCAD). This is the schematic ...
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1answer
119 views

Finding R for max power deliverable to R and determining the max power

This relates to max power transfer. Here's my circuit: simulate this circuit – Schematic created using CircuitLab My goal is to try and find the value of R for the maximum power that can be ...
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1answer
438 views

calculated Voltage explanation

The blue highlighted values are the answers, but can sombody explain how my teacher got 120v for the 4k resistor and 60v for the 2k resistor? the only one I could figure out is the right side where I ...
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1answer
44 views

Finding Thevenin equivalent circuit and using that circuit when terminals inside circuit

Sorry for the bad title, but I'm trying to get the Thevenin equivalent circuit and then use that circuit to calculate a current i. The problem I'm having is I'm not sure what to get the open circuit ...
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1answer
231 views

4-bit binary multiplier circuit

I have made this 4-bit binary multiplier circuit, but the product of, for example: B3B2B1B0 (1100) x A3A2A1A0 (0001) = P7P6P5P4P3P2P1P0 (00101000) and not 1100, What have I done wrong?