All Questions
Tagged with theory circuit-analysis
38 questions
0
votes
5
answers
153
views
Is it true that a sine wave is the only signal that does not change shape in a linear circuit?
This is from Microelectronic Circuits by Adel Sedra and Kenneth Smith.
The book says,
In fact, the sine wave is the only signal that does not change shape
as it passes through a linear circuit.
Is ...
- 270
0
votes
4
answers
130
views
Can we solve all linear circuits using only KVL and constitutive relations?
Can We Solve for Node Voltages and Branch Currents in Any Linear Circuit Using Only KVL and Constitutive Relations?
In circuits with a single loop, it's trivial to solve using only Kirchhoff's Voltage ...
- 270
1
vote
1
answer
90
views
Does KVL guarantee identical voltages/currents in similar circuits?
I have a question that is a bit abstract. Assuming I have two proper linear circuits, A and B, which have:
The same ideal components (for example, voltage source, inductor, capacitor, resistor)
The ...
- 270
0
votes
1
answer
197
views
Need help to find the natural response of an RC circuit
Here is the question I am trying to solve:
I am stuck with the point that I am not sure Vo is found as -50v or +50v. Another issue is that Ic(t) is calculated by derivative formulas or another simple ...
4
votes
4
answers
2k
views
Will the net current drawn by a microcontroller equal the current supplied by it
Purely a theoretical question.
Consider a microcontroller whose only job is to turn 1 pin high and in the process the microcontroller supplies I1 current throught the pin.
But suppose we have to turn ...
- 67
1
vote
1
answer
358
views
Meaning of the determinant of an ABCD transmission matrix
In a thesis, [1] I found the following statement:
To determine [characteristic impedance and] dispersion relationships for
an arbitrary reciprocal network having the transmission matrix
$$ \begin{...
- 1,332
1
vote
1
answer
614
views
How to deal with a negative resistor in Z parameters of a passive network?
This question is so basic but for some reason I am not seeing it: Assume an arbitrary passive 2-port network having only isotropic materials. This implies S21=S21 and Z12=Z21 (see https://www....
- 1,332
0
votes
3
answers
174
views
Transistor Analysis
Here is a problem I saw as an example of transistor analysis: (hFE is 50)
simulate this circuit – Schematic created using CircuitLab
The process is simple, the guy assumed that the transistor ...
- 167
3
votes
3
answers
461
views
Why doesn't electricty flow to earth ground when I connect my oscilloscope ground clip to a floating circuit?
There are two concepts I keep reading about that seem to be conflicting each other. Firstly, whenever there's a potential difference between two points, and those points are connected, electric ...
- 131
0
votes
2
answers
2k
views
Bipolar Transistor Inverter Circuit Analysis
I have been trying to understand this question and I'm just not sure what equation to use for the collector current.
I'm not sure if I need to be using an output voltage function of time?
All I have ...
- 33
0
votes
2
answers
157
views
Help me understand what happens with the circuit when an AC signal is applied
Consider this circuit.
Transistor is 2N2222A. Ic is chosen to be 10 mA.
Hfe is 225 for that current.
Resistors are calculated to have Vbe = 0.7V and Vc = 4.5V.
I am trying to understand what happens ...
- 847
7
votes
3
answers
3k
views
How do I really calculate these resistors?
I am learning about it.
I would like to focus on this circuit
I am trying to calculate R10 and R11.
I want Ic = 10 mA. Transistor is 2N2222A.
This is an amplifier. If I understood how amplifiers ...
- 847
0
votes
2
answers
788
views
Does a current source have a difference in potential?
I am doing a nodal analysis of this circuit.
I have found that \$ V_A = 10 V \$ and \$ V_B = -20 V \$ is it possible to have a situation like that? I mean a difference in potential between terminals ...
- 847
3
votes
1
answer
963
views
Degenerate circuit concept and its theoretical and practical implications
I came across with the term "degenerate circuit" when I was studying solving linear differential equations with Laplace transform. I have learned that a system is called degenerate when the ...
- 439
0
votes
1
answer
93
views
Is this negative resistor model valid for any type of LC self oscillating circuit?
Is the following negative resistance model valid for any type of LC oscillator? If not, what are the exceptions?
Image Source is from here
- 868
2
votes
1
answer
817
views
Parallel RLC Resonance bandwidth
Good day ,I need help in understanding a practice problem that my professor gave us.
A parallel resonant circuit has Q = 20 and is resonant at ωO = 10,000 rad/s. If Zin = 5kΩ at ω = ωO
what is ...
- 21
0
votes
1
answer
254
views
Deriving resonance frequency of RLCC circuit
I am trying to determine the resonance frequency of an RLC resonator with added capacitor, as shown below:
simulate this circuit – Schematic created using CircuitLab
Two cases are easy to ...
- 1,726
2
votes
1
answer
3k
views
Intuitive and iterative approach to understanding of blinking LED circuit
I've used following schematics to build blinking LED circuit and it worked.
I tried to understand how it works qualitatively without solving differential equations. By this I mean understanding ...
- 121
3
votes
2
answers
1k
views
BJT Voltage Divider Bias Circuit Theoretical/Ideal Model Help ..LTSPICE?
simulate this circuit – Schematic created using CircuitLab
I've been trying to study BJT Voltage Divider Bias Circuits. In particular, as they relate to their active region, amplification, and ...
0
votes
2
answers
282
views
"Current is pulled not pushed" they say. Doesn't the transistor working the other way around? [closed]
The emitter current is defined by hfe and the base current not the load. The load does not "define" Iemitter.
- 5
-3
votes
1
answer
107
views
Flow of electricity. Need explanation [closed]
simulate this circuit – Schematic created using CircuitLab
People are taught how to calculate this very simple thing, and the calculation goes from source plus to minus, and the diode is there ...
- 103
0
votes
1
answer
40
views
What determines current through a VS in parallel with a resistor?
This is more of a conceptual question with ideal voltage sources, I am fully aware of its impracticality, but bear with me for the sake of a theoretical discussion. Consider a simple circuit shown ...
- 79
1
vote
2
answers
251
views
Electric networks with an open-loop
This is a generic concept question that I encountered during the first day of an EE course. Our lecturer told us that electric circuits are essentially electric networks with closed loops.
I would ...
- 79
1
vote
3
answers
264
views
neutralize charge in series capacitors
I have a simple circuit as in the picture below. My question is why the negative charge -Q at the bottom plate of C1 moves and neutralizes with the positive charge +Q at the top plate of C2?
- 1,661
4
votes
1
answer
326
views
Help with AC circuit theory problem
I need help with the following AC circuit problem:
Given the circuit (attachment 1) with known data:
$$\underline{Z_3}=200(3-j4)\Omega$$ $$\underline{Z_4}=100(3+j20)\Omega$$ $$\underline{Z_5}=100(3+...
- 161
0
votes
2
answers
4k
views
Two batteries connected to a resistor
In the circuit shown here the conventional current direction is from V2 to V1 and is equal to 3 Amp. I understand the theory.
But, if I make this circuit with two batteries, according to the schematic ...
- 684
6
votes
3
answers
1k
views
Understanding optocoupler performance with collecor or emitter resistors
When using an optocoupler, is there a difference performance'wise whether using a collector or an emitter resistor?
When using a normal transistor the base to emitter voltage gain is approximately 1, ...
- 33.4k
0
votes
2
answers
60
views
Is symmetrical current perfectly symmetrical beyond analysis? [closed]
Lets suppose that a circuit was constructed with almost identical components and wires to a ridiculous accuracy. When we say that a current is equal due to symmetry after a branch in a node with ...
- 153
-1
votes
1
answer
125
views
Why thevinin is applied to voltage source
Why do we use superposition with independent voltage source? and it isn't linear(I mean homogeneity and additivity).
EX: independent Voltage source V = 4 volts is not linear(homogeneity and ...
- 189
1
vote
3
answers
153
views
Simple Theory question about Circuit Analysis
I have the following circuit.
I calculated it's transfer function, in the common way, to be: \$ \frac{Vo(s)}{E(s)} = \frac{-R_3}{s\ R_2R_4C + R_2} \$
Then i thought something else. Since there's ...
- 405
5
votes
2
answers
314
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, ...
- 405
2
votes
1
answer
140
views
Homework: DC circuit help
I need help with the following problem:
Find range of resistance R4 and voltage U4 so that the range of current I is $$I \in [-3A,-1A]$$
E=5V,
E4=6V,
Ig=1A,
Ig4=-3A,
R1=2ohm,
R2=3ohm,
...
- 149
2
votes
1
answer
5k
views
Norton's and Thevenin's theorems importance
Are Norton's and Thevenin's theorems used in real life? And in which situations?
I'm reading a circuit analysis book and I asked myself: do electrical engineers use these theorems to get current and ...
- 1,039
1
vote
2
answers
284
views
Help with DC circuit theory problem
I need help with this DC circuit problem:
When the switch is open, voltage between points A and B is 2V. When the switch is closed, through variable resistor \$R_{p}\$ flows maximum current, and \$R_{...
- 149
0
votes
1
answer
1k
views
Wireless Power Transfer Circuit Theory
I made this circuit, and it is working fine. But didn't understood the theory in it. How is it putting a frequency in the coil? It did not match with any of the oscillator circuits. And also it is not ...
- 43
2
votes
4
answers
980
views
Series/Parallel DC circuit analysis training issue
I'm blocked in this exercise. I don't get how I can compute R1/R2/R3 voltage.
Here's the schema :
simulate this circuit – Schematic created using CircuitLab
So I was able to calculate some ...
- 1,830
1
vote
1
answer
446
views
Calculate current in branch using Thévenin's theorem
E1 = 20 V
E2 = 5 V
R1 = 10 Ω
R2 = 20 Ω
R3 = 10 Ω
R4 = 10 Ω
R5 = 5 Ω
Calculate Ix.
It's obvious that the Thévenin's theorem should have been used, but the implementation is a bit confusing ...
- 113
1
vote
2
answers
921
views
Basic circuit analysis - diferential equation
This is the circuit I got from an example in a book "Practical Electronics for Inventors", on page 48:
How can one understand that \$0=R\frac{dI}{dt}+\frac{1}{C}I\$ implies \$I=I_0e^{\frac{-t}{RC}}\$?...
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