Questions tagged [math]

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

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32 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 ...
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3answers
93 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
64 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
28 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
139 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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24 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
76 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
56 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
117 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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47 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
36 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
154 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
109 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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32 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
56 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
127 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
90 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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0answers
61 views

How to calculate the rotation of stepper motor for winding a thread on a reel

A machine which can be used to wind the thread of exact length on a reel using two stepper motors, one for rotating the reel(Ymotor) and other one is used for traverse back and forward(Zmotor). So ...
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2answers
91 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
43 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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85 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
348 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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23 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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72 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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42 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
139 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
96 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
80 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
75 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
100 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
93 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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58 views

Help with determining the open circuit voltage

Can someone go through why Vxy= -84mV? Given the values off VB=180mv R1=22ohms R2=68ohms R3=150 ohms. Many thanks
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3answers
106 views

Mathematical help with Wheatstone bridge

This is a homework, so I won't ask for a complete solution, but can anyone tell me how should I approach this? I've been sitting now for hours without any progress, all that I know is the answer ...
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2answers
74 views

Where did this useful matrix decomposition come from for Nodal Analysis?

Background The equations formed when finding the nodal voltages of a circuit can be expressed using nodal analysis as a square system matrix \$\mathbf{S}\$ (lets say \$m\times m\$ where \$m\$ is the ...
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1answer
129 views

boolean algebra question regarding how to simplify a 5 input circuit

Background: I'm teaching myself computer architecture because I do not have a technical degree and want to learn this even though my finances won't ever allow me to have a formal education. I am doing ...
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2answers
70 views

I need an equation to calculate the time for a power percentage of a half cycle sine wave into a resistive load

I need to calculate the time a thyristor/triac needs to be on for a desired percentage of full power of each half cycle of the AC line input. On for the full half cycle will give me 100%. On for 1/2 ...
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0answers
46 views

Differential amplifier solving equations for iDS

In large signal analysis of differential amplifier there are some equations to determine iDS. If we simplify it looks like that : \$ \large 2x^2+2kx+k^2-2\frac{l}{m}=o\$ Is there an easy way to ...
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0answers
23 views

Price as a function of load on an electric grid(City modeling)

Thanks for your time. First some context and the actual question is marked further down. Context: I am modeling a city as a complex adaptive system and am building a model of an electric grid to run ...
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1answer
73 views

There is no math for adding the functions of two parallel filters. Or is it?

I want to add two "parallel" functions. Each of them describes the frequency response of that individual filter. Put in other words, I want to see what the frequency response looks like when the two ...
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1answer
86 views

Clarity on dB SPL calculation

Based on this post, let me assume that I have a input source of 94 dB SPL / 1 Pa that a microphone is picking sounds from. The microphone has a sensitivity of -46dBV/Pa , this gives 0.005012 V RMS/ ...
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1answer
40 views

Discrepancy in my dB SPL calculations

Having read through this post I tried an experiment. I connected a Extech sound level calibrator to a Type 4189 microphone. The output sensitivity of the microphone is 50 mV/Pa,-26 dB ± 1.5 dB re ...
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2answers
105 views

Deriving Capacitor Current Equation

I understand that the current through a capacitor is given by the capacitance multiplied by the rate of change of voltage. I also understand that this leads to infinite impedance for DC and virtually ...
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2answers
101 views

Fourier series coefficient for sin(wt+theta)

Am trying to find the Fourier series coefficient ck for the following function \begin{equation} x\left(t\right)=\sin\left(wt+\theta \right) \end{equation} Here is my work \begin{equation} c_k=\frac{1}{...
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2answers
318 views

Finding the average power dissipated in a resistor

Well, I've a series RL circuit that is powered by a voltage source. The input voltage is given by: $$\text{V}_{\text{in}}\left(t\right)=50+\frac{400}{\pi}\cdot\sum_{\text{n}=1}^\infty\frac{\sin\left(...
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1answer
46 views

Transforming a supply power [closed]

For a recent project i need to power a certain element with .7 amps and 5 volts. my input power is 5 volts, but i need to calculate a circuit for decreasing current. I looked for answers on google and ...
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4answers
127 views

Sinusoids represented using Euler's formula notation, confusion

EM plane waves are represented using the equation (ignoring amplitude) $$E(x,t) = e^{j (wt - kx)}$$ They are also represented in this form: $$E(x,t) = \cos(wt - kx)$$ I want to get the electric ...
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0answers
60 views

How to calculate the current produced by a solar panel?

The equation for calculating current when given voltage and temperature is known as the 5-Parameter model ie. \$I = I_{ph} - I_o[\exp(\frac{V + R_sI}{nV_t})-1] - (\frac{V+R_sI}{R_{sh}})\$ Since this ...
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2answers
67 views

Graphical nature of signal energy

In signals, we learn that the energy of a signal is the integral of its square. E.g. \$E=\int_{-\infty}^\infty x^2(t) dt\$ We know that integrals are the areas under the function in a graph. But ...

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