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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How to figure out the pinout of this embedded netbook (Asus EEE X101h) webcam?
Sometime ago my old Asus X101H netbook died with a molten cooler fan. I've extracted it's webcam, which I want to use for another project.
Now I'm trying to map the pinout of the connector. The ...
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0answers
75 views
GFCI red LED fault indicator circuit
Just kindly share what kind of input in the violet dot at center to inject so the red fault led would turn on?
When the GFCI no longer function, the red led lights up. I'd like to understand how the ...
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1answer
36 views
How to calculate the phase difference between current and voltage?
Using the next circuit and the components of
simulate this circuit – Schematic created using CircuitLab
\$R=20\Omega\$
\$L=25mH\$
\$V_{DC}=36\$
\$v_{s}(t)=50+\underset{n=1}{\overset{\infty}{\...
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2answers
57 views
A contradiction regarding flux conservation
Consider a simple circuit
Initially switch S was opened till steady state is reached and then it was closed. My understanding regarding inductors is that you can't have a SUDDEN change in current ...
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0answers
41 views
Boost converter output voltage error
I'm using LT3494a to generate 37v from 6v input. This is my circuit.
According to the datasheet, this chip can provide up to 40v output, so it should be able to generate 37v. Also, the simulation ...
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1answer
32 views
Consistent Current Output From Batteries To DC Motors
I'm new to ECE and as a beginner project I've taken apart an RC car and attached an Arduino to the DC motors with an L298N module for control. The goal is for the car to drive a certain path with pre-...
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0answers
35 views
PNP darlington pair calculations
I have a 20ohms discharge resistor connected to my PNP darlington pair. I have simulated the circuit in my mobile (every circuit app).please find the attachment for circuit. But here I'm unable to ...
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40 views
Resistance and voltage [on hold]
Will this circuit need the resistance?
Similarly what will be the prescribed voltage, resistance for these 3 leds of 3 watts.
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2answers
42 views
Total inductance of two Parallel aiding inductors each with an inductor in series
what would be the total inductance of this circuit?
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1answer
28 views
What makes the SCR burnt up?
I removed Pin 1 to trace nuisance tripping of this GFCI circuit, and the SCR blows up:
From this circuit:
Removing pin 1 will make the pin 7 trigger the SCR continuously. But why would the SCR blow ...
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0answers
36 views
Switched circuit analysis - getting rid of “glue” equations
I have the following circuit:
simulate this circuit – Schematic created using CircuitLab
I would like to derive 3 differential equations, describing it, since it has 3 dynamic components [Csh, ...
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1answer
43 views
Finding resistance and how many appliances can be connected
A household electricity system can be modelled as a fuse in series with appliances, all of which are in parallel across the 240V mains supply.
In one household there is a 16A fuse in series with the ...
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3answers
112 views
Power amplifier, does this circuit work?
I found that circuit for a power amplifier. Does it work? I want to build one for myself.
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0answers
47 views
How to go about finding the transfer function of a non-linear circuit?
Note: The concept of Transfer Function is only defined for linear time invariant systems. Nonlinear system models rather stick to time domain descriptions as nonlinear differential equations rather ...
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0answers
20 views
Question about LKC LKV
I was answering probably a simple questions and I dont match the same result using the different method to solve that circuit below:
My 2 resolutions:
KVL:
\$\frac{30-V}{4}+2\cdot I_x-\frac{V}{6} = ...
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0answers
30 views
Ideas for electronics related c++ projects [closed]
I am engineering student ,I have learnt c++ to advance level covering OOPS, polymorphism, inheritance, template. I want to apply my knowledge learnt in my electronics engineering of various subjects ...
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0answers
25 views
Calculating Load Power in a transformer circuit
I've been learning about AC circuits and they seem pretty straight forward, except when it comes to transformers. I have this circuit and I want to figure out the Voltage and Power at R2, and also the ...
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0answers
17 views
How to apply Thevenin's theorem in multivoltage(3) sources?
Here is a question I am not able to tackle as the requirement is to solve it by Thevenin's theorem.
The question is to find the value of current passing through 20 ohm. I can perform Mesh analysis ...
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2answers
66 views
How is voltage divided between two reverse-biased ideal diodes?
Suppose we have two identical ideal diodes (without any resistance or voltage drop). We connect these two diodes in series, in the same direction, and reverse-bias them with voltage V. Now we have two ...
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2answers
54 views
How to construct the DC equivalent circuit of a BJT amplifier
How would the DC equivalent circuit be constructed? I have a vague idea knowing that AC voltage sources are connected to the ground and capacitors are open circuited but what happens to the resistance ...
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1answer
39 views
Determine the value of Vx if the power dissipated by resistor Rx is 450W and Rx=50 Ohms
I keep getting figures that are out of these ranges. Maybe I am doing it wrong. So far I've been adding the possible voltages with 200V to get a total voltage, then using Ohms's Law to see if any of ...
1
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2answers
66 views
Two-port circuit with input/output duality
Suppose I have a circuit with two ports. One port is considered the input, and the second port is considered the output.
Assume it's described via
$$V_{out} = \frac{V_{in}}{2}$$
Now assume there's ...
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1answer
53 views
Apparent contradiction in AC analysis of BJT amplifier
Suppose you have the circuit:
For an AC analysis we can draw the following circuit:
Now my job is to find \$v_{out}\$, which can be easily found by:
$$
i_E=\frac{v_{in}}{R_E} \\
i_C=-\frac{v_{out}}{...
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1answer
91 views
Finding current through an LED in an amplifier using a BJT
Suppose you have the schematic:
My job is to find \$I_{LED} \$ knowing that the impedance of the capacitor in negligible against \$V_s\$. Here's my attempt:
I intend to do an AC analysis followed by ...
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1answer
30 views
Find admittance( G ) matrix of a resistive circuit
I am taking Signals And Systems class where I have to calculate the admittance parameter of a given circuit.
A given circuit for example:
This is tedious and calculating the parameters takes so long....
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1answer
23 views
NAND Simplified with xy + !x z
I've been trying to work on a few problems, though I'm not sure how to rewrite this a few circuits using only NAND/NOR -->
an example is shown below;
How am I able to rewrite only using NAND + NOR ...
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1answer
49 views
Can a system have constant phase response other than +/- 90 deg (and multiples)?
I have seen frequency responses where amplitude response is constant( pure delay) and where phase response is constant(pure integrator).
In an integrator the constant phase is -90 deg. In a pure ...
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1answer
57 views
Bypassing refrigerator door alarm piezoelectric buzzer
My appliances keep beeping at me. How can I deactivate or bypass this refrigerator door alarm buzzer without affecting the rest of the circuit?
I thought I could just cut/connect the wires at the ...
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3answers
88 views
Voltage in RC circuit with unknown frequency
We were given the task of finding the voltage drop across R1 of the circuit below with the following alternatives:
5.8V
4.8V
4.0V
10.0V
All given information is contained within the image, i.e. no ...
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2answers
65 views
Find Voltage of inductor in LC series circuit with resistor in parallel
I have a LC resonance circuit with a resistor between the capacitor and inductor:
simulate this circuit – Schematic created using CircuitLab
I want to find the Voltage at L1, more specifically ...
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2answers
45 views
Bosch Glue Pen: Bypassing automatic timeout [closed]
I have this Bosch hot glue pen. It has an annoying habit of turning itself off. I guess it's probably intended to be a safety feature or a battery saver, but really it's just a nuisance.
Can I modify ...
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4answers
141 views
Op-Amp gain calculation
I'm trying to find R4 that will make:
$$\frac{V_{out}}{V_{in}}=-120$$
The operational amplifier is ideal.
My attempt: In the '-' input there is a virtual ground, so the equivalent resistor above is ...
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2answers
71 views
Input impedance of circuit
Given current gain (hfe = 100), internal resistance (hie = 2000), reverse voltage gain and output resistance (hre = hoe = 0), compute input impedance for the following circuit.
The problem is that it ...
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1answer
136 views
Overcurrent protection for DC motor [closed]
I found a circuit to protect DC motors from stalling:
this is the schematic:
and this is the board I made based on that schematic:
When the power is connected to the circuit makes all LEDs on but ...
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1answer
61 views
How can I find the short circuit current across a and b?
In order to find R thevenin, I need to find Isc across a and b since there's a dependent source.
Based on my calculations, Vth=500/3V.
I've spent countless hours thinking about Isc,please help.
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1answer
43 views
Realizing 2 Resistors are in series in an RC circuit
I understand that when the switch is open, the capacitor acts like an open circuit & therefore the current in the capacitor branch would be equal to 0. When I solved the circuit using nodal ...
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3answers
32 views
Half wave sine form factor example
Hint: in my calculations below, to make math easier, i assume that the
diode = ideal(there is no 0.7 voltage drop across the diode)
Vrms = 0.707Vp => Vp = 14.1v, therefore Vp(load) = 14.1v ...
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0answers
45 views
BJT as a switch: what am I doing wrong? [duplicate]
I'm studying the following circuit
The image is explicit but as you can see the input measured in the upper terminal is a square wave with \$E_c\$ and \$-E_c\$ as levels.
Now I also had no trouble ...
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2answers
52 views
Bipolar class-AB amplifier analysis questions
I am analyzing the following amplifier schematic
Bipolar amplifier
I'm wondering if their are any transistors that need to be cooled apart from the 4281A and 4302A output stage transistors?
What is ...
4
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3answers
486 views
What is the value of the current (i) and what is the right way to do it? [duplicate]
What exactly went wrong with the below method?
Here, in the same circuit I am getting a different value for the current in the mid wire only by rearranging the circuit.
I was trying to solve this ...
2
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1answer
61 views
Nodal analysis in s-domain help
I am learning circuit analysis in s-domain from my textbook "Engineering Circuit Analysis by William Hayt, 8th Ed". I am struggling with the mesh and nodal analysis.
In the book at page 583, there is ...
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1answer
99 views
What's wrong with this Wheatstone bridge?
I was trying to solve this unbalanced Wheatstone bridge and found that the current $i$ in the mid wire is 9A .This result was achieved by using node voltage method.
Then I rearranged the same circuit ...
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0answers
25 views
For given circuit, does the current “io” through the branch equal zero after short circuit ? [2-port network]
The circuit is;
simulate this circuit – Schematic created using CircuitLab
For given 2 port network, Im shorting V1 to solve for y22 and y12 and apply a current source at V2.[Y-Parameters]
...
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0answers
31 views
Determine Y-parameters for given circuit. [Used Nodal Analysis]
I am trying to solve this circuit for past 3 hours, no success, so I am posting here.
simulate this circuit – Schematic created using CircuitLab
I used nodal analysis, I will go over the ...
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0answers
17 views
Snubber maximum ratings
I'm developing a home automation system, and using a triac to power on/off some lights.
My problem is that lights from other rooms when switched on/off are producing noise/spikes and flashing the ...
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0answers
18 views
Faraday's Law in the transient solution of Rl circuit
Consider RL circuit consisting of a battery , resistance , inductor , and switch .all components are in series .
If we close the switch at time t =0 the current will build up until reaching a maximum ...
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0answers
72 views
Trouble with my homemade induction heater
first of all, I´m not engineer, not physics and not "math-man", so you know this, I can afford explain my problem, I´m building an induction heater following the instructions found in net (I ...
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0answers
39 views
How to deduce the current function from the graph?
I want to express the current function based on the next graph
So using the slope and the coordinates in the third interval the current will be
\$i(t)=\begin{cases}
0\,A & 0\,s<t<t_{1}\,s\\
...
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1answer
72 views
Output current in collector of BC107
I am working on following circuit involving BC107 NPN Philips TO-92 transistor and voltage source of 4.2 V.
simulate this circuit – Schematic created using CircuitLab
I got some confusion when ...
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2answers
81 views
Why the led isn't glowing? [closed]
Why doesn't the led glow?
I am trying to glow my LED For Making Project Of Detectore but it doesn't glow.
When i connect this circuit with my full project that time LED Wasn't Glowing After I ...
