Questions tagged [theory]
Theory is a contemplative and rational type of abstract or generalizing thinking, or the results of such thinking. Depending on the context
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140 views
Why is Line coding called "Line coding"?
Why is line coding also called digital base band modulation named "line coding" where does it come? and how is the name it to modulation
2
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1answer
175 views
About power dissipation of capacitors and inductors & I-V phase difference
For instance, The Art of Electronics (by Horowitz & Hill) states that
ideal capacitors cannot dissipate power, even though current can flow through them, because the voltage and current are 90° ...
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4answers
72 views
Difference between Message and Signal in Communication Theory [closed]
What is the difference between a message and a signal in Communication Theory?
It seems to me that often they coincide, is this always?
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0answers
52 views
Can someone confirm my derivation of the generalized power law from Practical Electronics, 4th edition?
I dont know how to use LaTeX, so I used Mathcha and took a snip from there.
2
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1answer
60 views
Matching via sizes to trace widths
Let's say I've determined a trace width (\$t_w\$) for a trace, and now I want to determine the size of a via on that trace.
My intuition is that to maintain the same amount of copper as the trace ...
7
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1answer
273 views
Why is BMC/k-induction used in RTL formal verification?
One popular approach for proving safety properties in formal verification of RTL designs is a combination of BMC and \$k\$-induction, which appears to stem from "Checking safety properties using ...
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0answers
50 views
Is there a method to convert a Butterworth response into Chebyshev and Bessel responses?
I wonder if once there is a completed/aproximated a design model of any of the responses mentionated, it can be operated mathematically (or there is a method/recipe) to generate the other responses?
...
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2answers
565 views
How is the slope of the frequency response of an analog active filter defined?
I have seen different types of filters, and different slope values at -20 db, -40, etc.
The literature says that the order define the slope, but how? How can it be mathematically justified?
For ...
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1answer
90 views
How/where does a generator + motor dissipate heat?
I've got a mystery that I can't wrap my head around.
A generator is generating 1 kW of electric power. The current goes through copper cables to a motor, which is consuming say 950 W of electric power....
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1answer
96 views
ESP32 Input Voltage Divider, Concept
Thank you for reading. I have read many other voltage divider explanations and calculators on this site as well as the web.
My application is using a voltage divider to lower a possible 5 V signal (...
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4answers
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 ...
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2answers
133 views
How to explain the strange results from this circuit (op-amp : differential amplifier?)
I have a differential amplifier. Problem of "gain" of the op-amp or "how it is wired."
I have simulated this as a voltage source controlled voltage (VofV.)
As a generic amplifer.
...
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2answers
101 views
Switching DC battery on ideal choke?
(Google translation). A switch is activated at the instant t = 0 in a series circuit containing a battery of voltage U (ideal) and an inductor L (ideal). I am in doubt with the answers I have found on ...
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1answer
79 views
Is it possible to implement one 8-way 1-bit multiplexer?
I'm sorry, but shouldn't 8-way have 3 bits in order to traverse every address? Anyway, I have here a problem, and I am not sure if my solution is correct.
The problem: Given the boolean expression
\...
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2answers
75 views
Is it possible to syntethize this Voltage Transfer Function?
I have the following voltage transfer function:
$$
H(s) = \frac {a s^4 + b s^2 + c}{p s^4 + q s^2 + r}
$$
Where \$a, b, c, p, q, r\$ are all real constants.
The only method I have been taught to ...
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2answers
161 views
Does the frequency response \$H(j\omega) \$ exist for system with unstable poles?
This question arose from a discussion between me and TimWescott in the comments here. The question is:
Does \$H(j\omega) \$ exist for systems with poles in the RHP (unstable poles)?
My own answer to ...
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2answers
106 views
How many newtons are there in one coulomb of charge?
Or, I should have said, how many newtons of force does one coulomb of charge exert? At a distance, presumably, of one meter? Since N/C is supposedly equivalent to V/m?
P.S. What are the values for a ...
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1answer
40 views
What does it mean that in a point Α of an electrical field the voltage is -7?
The title. I am really confused. Does it mean that you need to spend 7J of energy to move Q=1C from there to somewhere where V=0, does the Q you move matter? Does it mean you need to spend 7J to move ...
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2answers
83 views
Theory: Can power cables induce AC voltage in human body?
In a demo video (which I unfortunately can't share) a man makes the following setup:
Multimeter on 200 V AC settings with one pin in the ground socket of a conventional mains power socket.
Right ...
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1answer
52 views
Op-Amp Impdance Question
For the problem shown above since there is no current travelling through the input of the Op-Amp can we assume that the Op-Amp is acting ideally? And using this assumption can we ignore the output ...
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1answer
92 views
How to analytically find node voltages in a voltage doubler?
Given a voltage doubler circuit:
simulate this circuit – Schematic created using CircuitLab
You can figure out what should happen in stead state if \$R_L=\infty\$ and \$R_s=0\$. In that case, \$...
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1answer
63 views
Given the power spectral density, how do I calculate the bandwidth and total power of \$X(t)\$?
Given the PSD (power spectral density), \$S_x(f)\$, of a signal, how do you calculate the bandwidth and total power of \$X(t)\$?
I think I have the bandwidth but how can I get the total power of \$X(t)...
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1answer
50 views
Blocking capacitor causing signal to go low in otherwise working amp/rectifier circuit
I'm making a simple amp > voltage doubler rectifier circuit to drive an lm3916 meter circuit and when simming to choose between JFET, BJT or OpAmp (just for my learning, I'm looking to a Jfet in ...
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2answers
74 views
Theory Question: Speakers don't work unless I poke soldered points with screwdriver
In case you couldn't tell by the title, I don't really have any idea what I'm doing with electronics. Something happened though, and I am really curious about it. Don't know how to ask it specifically,...
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1answer
34 views
Operative Definitions of Memory in Circuits
I've been studying Memristors (non-ideal) and some related circuits depending on pinched hysteresis of the IV for use in memory. I'm still puzzled by the lack of general framework for what constitutes ...
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2answers
189 views
What is Ethernet diff. pair referenced to between connector and magnetics
This is a little bit confusing part. I clearly understand that in ethernet cable fields are coupled between wires of differential pair. On PCB on IC/PHY side it is also known that differential pair ...
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0answers
39 views
A circularly polarized EM wave is perfectly absorbed by any interface?
According to the Fresnel equations, the effective reflectivity of an arbitrarily polarized electromagnetic wave is given as:
$$
\Gamma = \frac{\Gamma_p + \Gamma_s}{2} ,
$$
where \$\Gamma_p\$ and \$\...
0
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1answer
61 views
Parallel LC circuit Q factor inductance role
I'm wondering why Q factor in parallel LCR circuit is proportional of C and inversely proportional to L according to the formula \$Q = R \sqrt{C/L}\$ completely lost here
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1answer
69 views
What are the modern uses of SPI and I2C protocols [closed]
I have been using I2C and SPi for a few years now, but as I begin working with USB, I realize it is much faster. I still see devices with 2 MCUs that could potentially communicate faster with USB, but ...
1
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1answer
120 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{...
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0answers
49 views
Algebraic Data Type
I understand the concept of algebraic data types, but I don't see in what context they are useful or when they would be beneficial. When should I consider using them and how are they useful in ...
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1answer
104 views
Diodes and resistors theory
I came across a problem which I cannot calculate by theory.
How does this circuit with diodes and resistors work?
In the above diahram, I can calculate the current simply by subtracting the voltage ...
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1answer
90 views
Early Deadline First (EDF) scheduling in real-time systems feasibility test proof
I am trying to prove Theorem 6.2 on page 127 of the book Real-Time Systems by Jane W. S. Liu:
http://www.cse.hcmut.edu.vn/~thai/books/2000%20_%20Liu-%20Real%20Time%20Systems.pdf
It is based on Early ...
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1answer
159 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....
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3answers
469 views
Possible to control a transistor by BC terminals?
I'm thinking about a strange working mode: the CB part is forward biased and trying to control EC current by CB current.
EB is reversed.
May it work?
Transistor is BJT.
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2answers
83 views
Why passive component has better drift characteristics than active components had?
I came across this paragraph in the classic reference Op Amps For Everyone by Ron Mancini where it says on the first page:
Many attempts has been made to make a stable amplifier, but temperature ...
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1answer
28 views
Common emitter amplifier's \$R_C\$ breaks
What happens if the collector resistor breaks (its value goes to infinity) in a textbook example circuit?
I assume that \$ I_C \$ hits zero, \$ U_{CE} \$ decreases until the transistor goes into ...
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7answers
2k views
Why is power of a signal equal to square of that signal?
Is there any logic as to why the power of a signal \$\mathrm{x(t)}\$ is taken as \$\mathrm{x^2(t)}\$?
I searched everywhere and there's no clue. My professor told: "It's a standard result so shut ...
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2answers
152 views
Why does triode voltage drop change as a function of grid voltage?
Imagine a thermionic diode connected in series with a resistor \$R\$. The circuit is hooked up to a voltage source \$V\$. The diode conducts a certain current \$I\$ and \$\Delta V_\text{diode}\ + \...
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5answers
339 views
Is it possible to "hash" a circuit board?
I'll preface this by saying I'm a software engineer by trade and have very little EE knowledge.
In the software world, one can take all the bits that make up a file and generate a hash for a file. ...
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1answer
85 views
Applying Thevenin's theorem between 3 points
I'm studying about transistor polarisation and got confused by this application of Thevenin's theorem, can someone please explain why eT is between B and M and why Vcc stayed even though it's not ...
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0answers
83 views
Type 1 surge protection: parallel or series?
Type 1 surge protection devices (SPDs) are installed at the outside edge of electric service, usually between the power meter and the meter base/socket, and protect the entire house. But how do they ...
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3answers
365 views
Energy Transformation in Flyback Transformers
I am trying to understand how is energy transferred as a current to secondary of flyback transformer. First due to the dot convention and secondary side diode, current will not flow in secondary and ...
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2answers
106 views
Why do I get such high values when calculating the power dissipation of MOSFET in boost-converter circuit?
I'm a hobbist interested in electronics so I don't have any "professional" training on that.
Currently I'm trying to design a boost converter and now I'm stuck at some calculations.
I wonder ...
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5answers
2k views
Is Gaussian noise equal to white noise?
If noise on a signal is randomly fluctuating in time domain around its mean following a Gaussian normal distribution (Gaussian noise), would this be equivalent to an constant intensity in the ...
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4answers
128 views
Relation between transmission line and circuit impedance
What is the relation between the impedance of lumped components and the characteristic impedance of transmission lines?
I have noticed that in some cases transmission lines are loaded with lumped ...
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1answer
58 views
Digital regulator for DCM Boost - How does it relate to duty cycle?
I really hope someone can help me here, I'm tearing my hair out trying to bridge the gap between control theory and electronics.
My aim is to control a discontinuous conduction mode boost converter ...
4
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6answers
1k views
How do computers output a signal without an input? [closed]
I'm curious about how an output pin gets turned on at a low level when there is no input like pressing a button to complete a circuit.
If you program a raspberry pi to turn on and off an LED how does ...
2
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5answers
558 views
Generalized Power Equation, Ohm's Law and Ohm's Power Loss?
I'll try to state my questions precisely as I can.
I'm a beginner in Electronics and since I have a background in Physical Chemistry and basic Calculus, the book Practical Electronis for Inventors, ...
2
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3answers
528 views
What exactly does a resistor's tolerance rating mean?
I thought that I had this pretty much figured out over 30 years ago during my initial schooling, but various answers posted to a support forum of a major semiconductor manufacturer(name withheld to ...
