Questions tagged [math]

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

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1answer
31 views

Find the phase angle between two functions

Apologies if this is better suited for a mathematics forum, it's from my circuits textbook so I've decided to post here. Below is a practice problem from the textbook, with the provided solution. If ...
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1answer
23 views

How to calculate fuse i2t rating when current is known?

How do I convert the fuse current rating to the i2t value? For example, in this circuit simulator, when adding a fuse, the only values that can be specified are the i2t value and resistance. The fuse ...
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0answers
39 views

What are the variables describing in this equation?

For my course, we have to use this formula when calculating the speed of a DC motor. I know V, I, R and Φ, but i'm not totally sure what c, Z, p and K are. I think p is number of poles in the motor. I ...
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2answers
45 views

How many wiring combinations exist for an *n*-pin cable/connector?

This is more a pedantic question about the possible number of wiring permutations inherent to an n-pin connector and cable. Note combinations imply that elements may be used more than once (combined),...
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1answer
59 views

can anyone point me towards the math behind biquad antennas?

I've looked everywhere for the equations to build a biquad antenna. Calculators are nice, but I want the math. Just point me In the right direction since I've had zero luck on Google.
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0answers
21 views

How can I simulate different realizations of these joint random variables with the given PMF?

If I have two Discrete Random variables X and Y which have the joint PMF: \$P_{xy} = c(x^2 + y^2)\$, where \$x\$ belongs to {1,2,4} and \$y\$ belongs to {1,3} I tried to make two discrete random ...
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1answer
176 views

Find the inrush current in the capacitor [closed]

How can I find the inrush current value of the capacitor in the following circuit: simulate this circuit – Schematic created using CircuitLab When \$R_1=R_2=10\$ and \$L=10mH\$ and \$C=1\mu F\$ ...
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1answer
799 views

how to solve this op-amp circuit?

I would appreciate some help solving this simple circuit which I'm trying for some time but can't seem to match with the given answer. Aim is to find output voltage \$V_o\$ for the given input ...
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1answer
43 views

OpAmp as Differential Amplifier Equation

I am currently reading a (german) textbook about Operational Amplifiers. In the Chapter about the use as an differential amplifier, the authors derive the equation for the output voltage (for the case ...
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0answers
42 views

Output of a linear system with discrete feedback

I have this problem here that I had trouble with few years back and I still don't understand https://imgur.com/At2BbWe With a T period discretization on the feedback and a first order hold after it. ...
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1answer
36 views

Singular interval condition for Multi input in Optimal control

The definition of singulr interval is shown in Figure. I've struggled with this problem. I think the solution of this prob is "because if the E_j matrix is not singular, it means the System is ...
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0answers
35 views

Laser-Doppler Velocimetry. Math/measurment problem

My team of 3 were tasked to measure the speed of a disc with a small hole on it using laser-doppler velocimetry (measurement and sensor technology class). After doing the measurments and writing them ...
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1answer
52 views

Converting pulses to RPM

I have a question about how to take an output from a sensor and calculate RPM. The sensor produces a square wave at a maximum frequency of 1kHz. So I think I have two options: Count rising edges in a ...
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1answer
36 views

How to calculate Vce and Ic from transistor gain

How would I calculate Vce and Ic from a given DC transistor gain? Thanks.
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3answers
885 views

Conundrum: High pass filter passes DC?

Consider a simple C-R 1-pole high pass filter. Apply a step input. The rising edge of the output rises up and then exponentially decays back to zero. Integrating the output over all times yields a ...
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0answers
46 views

What is the formula used for servo motor positioning?

First of all, to be clear, I am not very experienced with mathematics applied to electronics but I have had the interest for a while. What is the right approach to knowing the position of a servo ...
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2answers
87 views

How to prove that \$I_3=Vi/R1\$ in a darlingtonpair circuit with opamp when \$\beta_2\to\infty\$? [closed]

I have the following circuit: simulate this circuit – Schematic created using CircuitLab How can I prove that \$I_3=Vi/R1\$ when \$\beta_2\to\infty\$?
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0answers
22 views

How to rederive the formulas for parasitic capacitance of a spherical tesla coil topload

I wanted to prove, or rederive, the formulas for parasitic capacitance of both a toroidal topload, and a spherical topload used for a tesla coil. I thought I'd start with the spherical because the ...
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2answers
152 views

Does combinational and sequential logic correspond to some mathematical logic systems?

Is it correct that the functionalities of digital circuits are divided into combinational logic and sequential logic? Is combinational logic the same thing as propositional logic in mathematical ...
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2answers
110 views

Using boolean algebra, simplify $$y = \bar{s} \cdot \bar{u} + s \cdot \bar{u}+s \cdot u$$

I have the following function, that I want to minimise using boolean algebra: $$y = \bar{s} \cdot \bar{u} + s \cdot \bar{u}+s \cdot u$$ Here's my attempt: $$\bar{s} \cdot \bar{u} + s \cdot \bar{u}+s \...
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2answers
103 views

Producing simulated thermal noise

I’m trying to simulate thermal (Johnson) noise. As I understand it, thermal noise follows a Gaussian distribution, power at the receiver is given by: $$ P = 4kTB $$ And the RMS voltage is given by: $$ ...
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2answers
78 views

Differentiator cut-off frequency

A practical differentiator has two cut-off frequency but can no longer perform differentiaiton after first cut-off. After first cut-off there is a 20db per decade gain reduction but why does this ...
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2answers
105 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
95 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
72 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
97 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
20 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
61 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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0answers
35 views

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
29 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 ...
3
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1answer
186 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
207 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
28 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
90 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
31 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
59 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
89 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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0answers
68 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
36 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
101 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
72 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
135 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
293 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
28 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
78 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
220 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
126 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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1answer
45 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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