Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

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.

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.

Most notably the concepts of derivative of a function and integral of a function are the basic building blocks for the time-domain models of reactive circuit elements like capacitors and inductors.

See Wikipedia on calculus.

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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/amplification is possible by doing a calculation of two…
Mister D
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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 RCL and dependent sources ends up in an H(s) which…
emnha
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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: $$ i=10e^{-2000t} Amps $$ Calculate the total charge in…
user27810
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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 variable current load consisting of several DC motors…
Graham
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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). $$\tau = RC $$ I also understand that when discussing…
Kendall V
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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 conditions in circuit for given parameters and then…
Keno
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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\$. Why can we say that the average voltage obays the…
Looper
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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}\$ over \$T\$ We know that…
user97662
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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 circuit under DC conditions. Neglecting all AC…
Jason_L_Bens
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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 pad @1.5W/mK 2) using a unique shared heatsink…
Gianluca G
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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 conditions like this. The voltage source is a DC voltage…
emnha
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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 to discharge from Va to Vb when connected to a…
Bruce Lee
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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: $$Ri(t)+\frac{1}{C}\int_0^ti(t)+L\frac{d\:i(t)}{d\:t} = v_s(t)$$ for this example let:…
Blue7
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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. So, I think ~150 Watts was enough. I'll explain…
David Bensoussan
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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
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