Questions tagged [math]

Math or Mathematics is the abstract study of topics such as quantity (numbers), structure, space, and change.

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2answers
55 views

How does an XOR phase difference detector behave when input frequencies are different?

How does an XOR phase difference detector such as AD8302 behave when input frequencies are different? Does it give meaningful results when the frequencies are close but different? Is there a simple ...
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1answer
65 views

How do I calculate how long it will take for a capacitor to discharge when shorted?

If I know the capacitance, series resistance, and the voltage it is charged to. I tried using a graph y=x/0.003 Where y is current and x is voltage, but now i'm lost, because I don't know where to put ...
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1answer
67 views

Energy consumption of mathematical operations

Are there any general estimates of the (relative) power consumption of mathematical operations in electronic circuits? Surely, this is chip-dependent, but for example, ...
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1answer
51 views

Finding the transfer function of a opamp circuit with 3 opamps

I have the following circuit: I know that \$\text{sig}_+\$ is a voltage that is \$n\$ times bigger than the voltage at \$\text{sig}_-\$. Question: If \$R_g\$ is a coil with the value \$63\space\text{...
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0answers
16 views

Multipole Network Power Calculation

How do we calculate the DC power consumption of a multipole resistive network, if we know the currents of all the poles (pins) and all the voltages between the poles? Let's say for example, that we ...
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1answer
57 views

Equations in electrical circuits

This might be more of a math question but when solving electrical circuit problems, if f(x-1)= x What is f(x)?
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Why Altium AC simulation lacks of the math functions available in other analyses?

In Altium Designer, Mixed Sim simulation, AC analysis, the plots can be modified adding arbitrary combination of waveforms, but for some reason, the Edit Waveform dialog lacks of the mathematical ...
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1answer
25 views

Suspicious definition of erlang distribution in Verilog-2005 spec

The $dist_erlang function in Verilog-2005 takes an argument called mean. Some information about the ...
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8answers
5k views

Why is impedance represented as a complex number rather than a vector?

I am trying to understand why impedance is not represented using vectors. I assume it is due to complex numbers having the property that $$j = \sqrt {-1}$$ but with my limited knowledge I can't see ...
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1answer
178 views

Why is this two-inductor circuit first order?

I have the following circuit with two inductors. Apparently this is a first order circuit (judging from my solutions for \$ i_1, i_2\$; and circuit simulations) but it's not intuitively clear to me ...
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3answers
103 views

Zeros and poles in the following bode plot

According to the definition, zeros are the frequencies which make transfer function to be zero, and poles are the frequencies which make transfer function to be infinity. The definition can be seen ...
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3answers
1k views

Solving an ideal opamp-circuit leads to a contradiction

Well, I am trying to analyze the following circuit: simulate this circuit – Schematic created using CircuitLab When I use and apply KCL, I can write the following set of equations: $$ \begin{...
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1answer
26 views

RC Calculation With Charge Already On Capacitor

Is there a formula for charging/discharging a capacitor which is already charged to a certain voltage? For example, if I charge a capacitor to 3v, then switch to a 1v power source, how can V(t) be ...
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6answers
89 views

Way to show that the current through a Darlington pair is determined by the emitter resistor

I have the following circuit: simulate this circuit – Schematic created using CircuitLab Is there a way to show that the current through \$\text{R}_1\$ is given by \$\text{V}_\text{i}/\text{R}...
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0answers
30 views

How to Select Prony Method Order?

I'm implementing a Prony decomposition to analyse power system signals in python. I think the code is generally working, but reconstructing a signal from the decomposition shows that it's not "perfect"...
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1answer
54 views

Why don't these even/odd mode transmission line results math up?

In Pozar's Microwave Engineering, he analyzes the Wilkinson power divider using even-odd mode analysis. His results match the expected values and power conservation is satisfied. Similar derivations ...
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1answer
65 views

How can I calculate the sparks when I discharging a big capacitor?

Several years ago I've tried to find answer to this question but I couldn't find the answers. I hope you help me. Because my job I have to discharging constantly "big" capacitors ( 400 vdc, 300 ...
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54 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 ...
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0answers
34 views

Calculating differences in gyro values

I want to draw a distribution of the change in gyro values (my values are coming from android). I read here that magnitude is relevant. I came up with 2 ideas for formulas, but can't quite make sense ...
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2answers
100 views

What is the RMS value of this waveform

I would like to know what is the RMS value of this waveform. I would like to see the mathematics. I ve done the mathematics but it seems that the result has a lot of terms ... If some approximations ...
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3answers
71 views

Fourier Series Concept

Hello, I am learning about the Fourier Transform, and I can do the math, but I'm having trouble with the fundamental concepts. From my understanding, the Fourier transform allows us to see the ...
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1answer
44 views

Delay between steps, given speed in mm/min [stepper motor]

I'm building a device that have to move in orders of thousandths of mm per minute. I've got suitable stepper motor and driver, it is working correctly but I'm unable to figure out the formula needed ...
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1answer
189 views

Why are complex numbers used in electrical engineering? [duplicate]

When I was in high school, I asked a physics teacher "Why do we use complex to calculate stuff with electricity?" (something along that line) and he said "Because it just happens to work" without ...
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0answers
25 views

Battery Charge and Discharge Time Calculations

I am performing some calculations but struck with confusion whether I am doing it correct or wrong due to contradictions of these calculations on different calculators websites. I hope here someone ...
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1answer
77 views

Math steps to get to answer

I have a issue understanding the math steps used to simplify an equation after deriving it. I would be grateful if someone would show all the steps taken to get from equation 1 to equation 2 shown ...
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1answer
128 views

Calculate battery discharging time?

Being far enough from everything about electrical engineering and so on, I'm sorry in advance for a dumb and possibly asked here in threads earlier such question. I have only the next data on ...
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2answers
121 views

Why is RMS used for P=VI (where there are no squares)?

I understand why RMS values are used for $$P = {\bar{v^2} \over R}$$ because \$\bar{v^2}\$ would be the "MS" so to speak, and then by square rooting we get the "RMS" (\$\sqrt{\bar{v^2}}\$), which ...
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0answers
58 views

Laplace Transform Question

looking at laplace transform for electrical applications, I don't understand how the provided answer works? Like how did they get the e^(-sT), through using the laplace conversion table? And also, ...
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1answer
40 views

Observability matrix different forms

The observability matrix formula is present in two forms in textbooks. My question is about which one to use. the first one: the second one: Now when applying both on the same system, I get ...
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2answers
162 views

Is a CPU declarative?

I know that this might seem like a stupid question, because declarative is not really an electrical term. I'm having a discussion (argument) with someone who is a functional programming fanatic, and ...
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2answers
151 views

Is there a mathematical proof that reactive power regulates voltage?

So after studying the power triangle and trying to conceptualize real power and reactive power, I seem to have come across a contradiction, at least in my own head. Most explanations disregard ...
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0answers
39 views

How does shifting Product/Divide Block work?

I've just learned about PID MRAC using MIT Rule, and to build it in Simulink I need to use the Product/Divide Block. https://www.mathworks.com/help/simulink/slref/product.html This is a figure from "...
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1answer
47 views

Syntax of complex numbers [closed]

In inductive reactance equation \$X_L = j2\pi fL\$, why do we write "j" in front of "2πfL"? Does it matter where we put it? Could you show me example where denoting real and imaginary number makes ...
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2answers
57 views

Difference between four matrices of state space?

I already know that there are two common types of representations used for mathematical modelling. One is transfer function and the other is state space. When dealing with state space representation, ...
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2answers
132 views

Question about the accuracy of integrated resistors

I'm studying the implementation of resistors in integrated technology. In particular the books deals with the accuracy of the obtained resistors. It says: Then it says: "We observe that the value of ...
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1answer
92 views

Efficiently calculate \$-x-y\$ using a single adder

I would like to know if there is an efficient way of implementing the operation \$-x-y\$ on an FPGA using only a single chain of adders or subtractors, roughly equal in length to the maximum number of ...
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2answers
92 views

please explain this fourier equaton

reference from here why are there 2 exponential terms on right side of equation in red box ? i know euler identity but why does ,the left side is trigonometry form when n=1 equal to exponential ...
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1answer
44 views

Trying to find value of two capacitors using resonant frequencies in three conditions, but wrong formula is derived

I was trying to find capacitance of two capacitors in the following way. Connect each capacitor individually to a same inductor and find resonant frequency in each case. Connect the same capacitors ...
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0answers
160 views

Diode sine wave shaper - location of break points

I'm attempting to generate a sine wave from a triangular wave using the diode breakpoint method where the sine wave is approximated by multiple straight-line segments. Where should the breakpoints be ...
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3answers
2k views

Implementing an absolute value function in C

I am implementing a function to find the absolute value like this: uint16_t absolute_value(int16_t n) { int16_t mask = n >> 15; return ((n+mask)^mask); } ...
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2answers
758 views

How to find the right smoothing capacitor for rectification circuit

I am creating a power supply which will need to convert the 24vac to 5vdc. I am thinking of using a rectifier to convert ac to dc, then a capacitor to smooth out the voltage, then an LM2596-5 to drop ...
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0answers
37 views

How to convert T matrix to Z matrix in two port network?

How can I transform a T matrix to become a Z matrix for a two-port network? I found the following conversion to get the T matrix from Z matrix from here : https://www.tutorialspoint.com/...
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0answers
81 views

Find the transfer function of an opamp circuit

I've the following circuit: simulate this circuit – Schematic created using CircuitLab I need to find the transfer function of this circuit. I did the following: $$V_+=\frac{R_1}{R_1+R_2}\...
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0answers
52 views

Cooling Peltier Maths

I want to construct a peltier cooling system. However, I have limited mathematical skills. Can I ask how to do the maths to calculate how much temperature differential can a specific peltier cool ...
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4answers
325 views

Class A amplifier - Transistor Q-Point calculation

Reference: http://www.learningaboutelectronics.com/Articles/How-to-find-the-q-point-of-a-transistor-circuit I am trying to understand this q-point calculation. I recently asked a question about the ...
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1answer
155 views

DC Analysis of Transistor Circuits - Double vertical line symbol

I have stumbled twice across this symbol || being used in the analysis of transistor circuits. An example can be seen at this address: http://www....
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1answer
82 views

Second order RLC circuit problem about signs

Consider this circuit. Which is a second order RLC circuit. The problem asks for value of \$\phi\$ from the initial conditions. I took the first derivative of the equation by hand but as you'd see ...
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1answer
76 views

Impedance load matching

So I've done this so far, and know one of the components is a 50ohm resistor. However I dont know where to go from here. How do i decide if its an inductor or a capacitor? This is a past paper exam ...
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2answers
108 views

Current in charged RC circuit

I've the following circuit: simulate this circuit – Schematic created using CircuitLab The capacitor is charged up to 10 V according to the following formula (when the switch is closed): $$\...
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1answer
115 views

Maximum safe working voltage of capacitors

The answer is 30kV. My method led to an answer of 41KV, where did I go wrong? I believe I cant just add the Vmax(s) at the end, but what would I do instead and why?

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