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Questions tagged [calculus]

Anything related to (differential and integral) calculus, i.e. the branch of mathematics concerned with the manipulations of infinitesimally small quantities. Concepts from calculus are often used in engineering to build more complex and accurate models of physical systems than those which can be built using basic algebra alone.

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How to derive a generalized equation with respect to time for voltage across the inductor & current in an RL circuit with a DC PWM source?

Circuit connection: I have this resistor (96 Ω)-inductor (990 µH) circuit connected to a PWM source of frequency 62.5 kHz; And ...
in.yssh's user avatar
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Getting temperature dependence for a beta multiplier circuit

I am currently working on designing a beta multiplier voltage reference, and came across this paper. I am slightly confused as to how they ended up with equation (6) after taking the derivative of (5) ...
soccernismo's user avatar
1 vote
1 answer
69 views

Discrete Fourier transform for musical analysis

I am a senior in highschool and am currently trying to conduct an exploration on Fourier analysis, specifically using the discrete Fourier transform to analyze a chord played on my piano. Basically I'...
Ralph Khouri's user avatar
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Can Watt’s law be derived from the Ohm’s law without using calculus?

Unlike Ohm’s law Watt’s law is not a fundamental law of electronics, as it can be derived from other fundamental laws of electronics. In the derivation above (see the pic) I used definition of current ...
ARNOB Chatterjee's user avatar
3 votes
3 answers
422 views

Finding Vrms over time

The plot of voltage over time is given in below plot. As you can see, \$V_{max}=2v \text{ and } V_{min}=0v\$ \$t1=2ms, t2=8ms, t3=5ms, \text{ and period, } T = 15ms\$ Question is to find \$V_{rms}\$ ...
user97662's user avatar
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1 answer
73 views

Please explain solution (TEM waves in spherical coordinates)

I have a question and a solution, I don’t know how the solution came up with the variables and values highlighted in blue in the solution part. Question: Solution:
zappi's user avatar
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-1 votes
1 answer
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How can an ideal motor do any work when the average of instantaneous power over one cycle is zero? [closed]

The attached screenshot illustrates the instantaneous power delivered to a purely inductive load as a function of time. How does an ideal motor (or perhaps some other purely inductive load) do any ...
artist_and_not_EE_by_training's user avatar
1 vote
0 answers
400 views

How to calculate total power required for an electric vehicle (ebike) design?

I wanted to design an ebike with good enough specs to satisfy my requirements, my first consideration was the power required to move the bike at my required speed and from there I can choose a motor. ...
AhmedH2O's user avatar
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2 answers
1k views

Transient Response, State Response, and Zero-Input/Zero-State, Natural and Forced

I would just like to know if each of these "responses" are the same. Are the words being used just synonyms of each other? Steady State and Transient Natural and Forced Zero-Input and Zero-...
Connor McDermond's user avatar
1 vote
2 answers
93 views

In-Series current source equation solving

I'm an electronic newbie, i was simulating this circuit on LtSpice and i found the result below, i tried with different methods (Kirchhoff's laws, Millman theorem, superposition) but i failed to have ...
menala.96's user avatar
1 vote
1 answer
277 views

Fourier Transform Time Scaling Property using f (frequency) or w (omega - angular frequency)

The time scaling property for a fourier transform is as follows: My book shows this property in terms of \$f\$; however, my instructor likes to use \$\omega\$. I have also seen this property written ...
Jake Baker's user avatar
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244 views

Capacitor constant power charge, constant current discharge curve

I have an (ideal) capacitor that is simultaneously being charged through a DC/DC boost converter (assumed constant power \$P_{in}\$) and discharged through a linear regulator (assumed constant current ...
Peter Power's user avatar
1 vote
1 answer
4k views

How to calculate kWh from amps

I'm getting measurements from an IoT device. This measurements are in amps (I get one every 2 min or so). I know the voltage of the device. From what I've seen online I can calculate the power in ...
Bdloul's user avatar
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3 answers
552 views

How to find mean value of square signal

I have a comparator circuit and I need to find the mean value of the output square wave. I have calculated it like this: \$Vmean=1/T*integral(U*dt)\$ from 0 to T and I got \$Vmean=-0.7896V\$ Can ...
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How to express a function in terms of singularity functions?

This is the question from the domain of the operational calculus related to circuit analysis. Here is the graph of the sawtooth function: It is asked to represent this function as a combination of ...
tenghiz's user avatar
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0 answers
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Calculate U(t) when capacitor C1 charges C2 via a resistor R

simulate this circuit – Schematic created using CircuitLab The switch SW1 is activated at t=10s and charge from C1 is transferred to C2. The power supply charges continuously with 1kV 1mA. How ...
Jonas Stein's user avatar
4 votes
2 answers
4k views

Capacitor sizing for known current load

Apologies in advance for the long question, but I've hit a dead end trying to work through an interesting capacitor sizing problem. I'm hoping someone here can help. Problem Description I have a ...
Graham's user avatar
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4 votes
5 answers
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why does RC time constant happen to equal 1/e?

I understand that the time constant in AC RC circuits is defined the value of resistance (in ohms) x the value of capacitance (in farads). Indeed, ohms(R) x farads(C) yields time (seconds). $$\tau ...
Kendall V's user avatar
0 votes
3 answers
486 views

I have 3.1V LED 20mA and wire 20 or more [closed]

How you calculate how much Volt battery you need? Like: 20 x 3.1V = 62V ....or is it something else? I want to wire them in series manner.
Karlkire's user avatar
4 votes
2 answers
401 views

Cannot predict closed-loop gain of this amplifier

This is the circuit I am currently analyzing: (link to LTSpice file) I am trying to predict each stage closed loop gain and overall gain (with all loops closed). First thing I did is calculate DC ...
lucenzo97's user avatar
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4 votes
5 answers
670 views

Average of a periodic voltage

I know that this question is math related, but I still don't get why we can say the following formula holds: I've a voltage \$V:\left[0,\infty\right]\to\mathbb{R}\$ and \$V\$ is periodic with \$T\$. ...
Looper's user avatar
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1 vote
2 answers
473 views

How to Find DC Step Response of Semi-Parallel RLC Circuit

Hi everyone, I find myself stumped on how to approach this problem since there is a resistor in series with the capacitor for what is otherwise a parallel RLC circuit. First off, I am attempting to ...
Big Gulps's user avatar
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1 answer
599 views

Mesh Current Method Circuit Analysis For AC Transient and Steady State Solution of RL Circuit

Hi everyone, I'm trying to find the currents through each branch for the above circuit using mesh current method (as I don't really know how else to do it), and end up with two simultaneous ...
Big Gulps's user avatar
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1 vote
2 answers
168 views

RLC without Source, finding the value of Resistance given I(0)

A capacitor of 1.58mF was charged by a battery of 12V and lies on the ground of an abandoned radio station. During a storm, an old telephone cable fell from a rack and one of its tip got in touch with ...
Lucas Lemos's user avatar
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1 answer
90 views

How to derive this formula from this schematic?

This is the voltage multiplier from the paper ,it said the rectified output voltage is given by \$ V_{out_i}\$= \$ V_{out_{i-1}}\$ +\$2(V_A-V_{ON})\$,\$V_A\$ is the AC voltage amplitude at the input;\$...
Shine Sun's user avatar
  • 317
2 votes
1 answer
917 views

Help in Thermal PAD and glue calculation (equivalence) in shared heatsink

Hello if I have 15 chips to dissipate 1W each (thus 15W in total), by math calculation, which of the next three possibilities is better: 1) using a unique shared heatsink @1.7K/W with 0.5mm thermal ...
Gianluca G's user avatar
1 vote
2 answers
1k views

DC DC Boost Converter - Why that high Ampere?

I have a question for the electronic experts of you! I want to create an DC-DC boost converter circuit for a project to get from 5V to 12V. Calculated with help of this site: https://learn.adafruit....
dessi's user avatar
  • 87
2 votes
1 answer
2k views

Using Fourier transform to solve current in a circuit with initial condition

I am trying to solve the inductor current for the circuit below by using Fourier transform instead of Laplace. The purpose is to see if Fourier transform also works for problems with initial ...
emnha's user avatar
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8 votes
1 answer
11k views

Meaning of Sigma in Laplace transform

I found the question below in a forum and I also have same problem. Unfortunately, there is no answer at all so I will post it here hope someone could make it clear. A gain relation in a circuit of ...
emnha's user avatar
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0 votes
1 answer
74 views

Find error in mathematical proof of electromagnetic fields

This is wrong but I can't figure out what is wrong, could someone help me find the errors.
Tina Hurlburt's user avatar
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1 answer
329 views

Confused about MOSFET math

So after the channel is pinched off in a MOSFET the equation that relates current and voltage through the MOSFET changes. What I am confused about though, is why in the derivation of this new formula ...
SarahK's user avatar
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-2 votes
3 answers
132 views

About calculus and resistors [closed]

how can you know the voltage of a circuit, after passing through a resistor? for example there is a 5 volt supply and a resistor of 120 ohms, what will be the voltage after passing through this ...
jfinizolas's user avatar
0 votes
1 answer
543 views

Ferromagnetic core with air gap

N=200 I=N*8A l=20cm=2*10^-1 d(delta)=1mm=10^-3 M=? M=(B/μ)-H How can I get the vector of magnetization? The relative permeability is not known. Everything I ...
Tristan Šneider's user avatar
0 votes
2 answers
274 views

How does the definition of electrical power follow from the chain rule?

Just a small question for clarification. Here's what I know: current I is defined by \$I = \frac{dq}{dt}\$ where q is charge and t is time voltage V is defined by \$V = \frac{dw}{dq}\$ where w is ...
user avatar
1 vote
0 answers
7k views

Why do simulated results differ to calculated results?

Why, when using a program such as multisim, do the simulated results within the program differ slightly to those calculated analytically. Would there be any reasons other than rounding errors in ...
ShadyBaby's user avatar
  • 117
11 votes
3 answers
7k views

Choose the better values (in terms of range) for resistors in this non-inverting op-amp circuit

These days I'm looking at operational amplifiers; from what I've seen, implementing them in a circuit is quite simple, at least when they are connected as "non-inverting". Determining the gain/...
Mister D's user avatar
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2 votes
1 answer
166 views

Trouble calculating time to drain a capacitor

Introduction I'm having trouble producing an equation that involving my MAX756 boost chip, a load and my 1.5F capacitor. Basically I'm trying to find out how long it would take for a 1.5F capacitor ...
Bruce Lee's user avatar
0 votes
1 answer
130 views

Explain this line of working when solving for the maximum power of a load resistor

Please, can you explain this line of working from the maximum power transfer theorem: For maximum power dissipation in the load, the condition given below must be satisfied $$\left. \frac{d^2P(...
Ashmar Barbour's user avatar
2 votes
3 answers
8k views

Inverse Laplace Transform of RLC Circuit

The voltage across the power source equals the summed voltage across the resistor, capacitor, and inductor at any time (t). This is shown in the equation below: $$Ri(t)+\frac{1}{C}\int_0^ti(t)+L\frac{...
Blue7's user avatar
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0 votes
1 answer
4k views

What is the general form of a first and second order dynamic system, in laplace and time space?

I have some of the information, but a lot of it is missing and I cant find a clear answer on the web. The general form of a second order dynamic system is: $$\frac{d^2x(t)}{dt^2}+2\zeta\omega_n\frac{...
Blue7's user avatar
  • 1,655
-4 votes
1 answer
393 views

Voltage calculation for the schematic [closed]

I would like to know how to calculate the output voltage for the following schematic. I would also like to see the calculations step by step. Right now I am not able to do this, I'm kind of new in ...
tzortzik's user avatar
1 vote
2 answers
3k views

Heating time of an aluminum plate

I'm designing a circuit for my 3D printer's aluminium heating plate (200x200 mm) and I wanted to be sure before buying resistors. Also, I'm using a Sanguinololu 1.3a. I want it to heat at 120° fast. ...
David Bensoussan's user avatar
2 votes
1 answer
3k views

Derivation of I_d of a self-biased JFET

I find that derivations of formulas are a lot more useful to me than just recitations of formulas. I'm looking at a self-biased JFET circuit, and I'm interested in deriving the quiescent state of the ...
Jason_L_Bens's user avatar
5 votes
1 answer
4k views

Need help interpreting a basic circuit question

In my Nilsson "Electric Circuits, 5th ed" book, there's this drill exercise near the beginning of the book. Here it is: Current at the terminals of the element is t<0: $$ i=0 $$ t>=0: ...
user27810's user avatar