# Questions tagged [math]

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

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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 ...
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 ...
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 ...
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),...
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.
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 ...
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 $C=1\mu F$ ...
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 ...
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 ...
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. ...
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 ...
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 ...
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 ...
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.
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 ...
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 ...
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 $\beta_2\to\infty$?
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 ...
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 ...
110 views

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 ...
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 ...
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 ...
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, ...
97 views

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"...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...