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

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2answers
88 views

Under what conditions does jw equal the laplace variable s in an electrical circuit?

Imagine I've got an electromagnetic actuator and solved the underlying differential equations. I got an solution for sinusodially excitation, as follows (just an example, no physical backround): ...
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2answers
38 views

Voltage Drop Across Wire With Fixed Load Wattage

I am looking for an equation to calculate DC voltage drop across wires that run a distance, with a switching regulator and fixed load at the end (a known wattage). Here are the specifics: The power ...
0
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1answer
57 views

Calculating amperage in a current source

How do I determine the amperage at "?" based on the selected resistors in this current source? Falstad Simulation I took a bunch of measurements from the simulation and plotted them. I know that ...
-1
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1answer
42 views

Digital Signal processing-Sampled period

Please can you help me with exam test preparation. I have take the below past year exam paper. I want to know if I am on the correct track and my answers are correct. x(t) = cos(50.pi.t + 30) ...
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0answers
37 views

What does K(k) mean in a transmission line equation

I'm reading through a book I have about transmission line structures. They frequently use the math: $$\frac {K(k)} {K(k')}$$ For instance, characteristic impedance: $$Z_0 = Constant \cdot \frac 1 ...
0
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2answers
130 views

Fourier transform of \$x(t) =t^2e^{-|t|}\$

I have to find the Fourier transform of this function. (- sign exists BEFORE modulus). I thought of using this standard result. If I split this fourier transform into this will it be correct ...
-1
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1answer
121 views

How to properly describe a Math Equation in Verilog to be synthesizable?

I have not been able to find a book or information in internet, about the correct way to describe a Math Equation in Verilog. With the correct way I mean for example, how to analyze the equation and ...
2
votes
1answer
63 views

Find dBm and watts of the attenuator?

The question says "A signal of 40 dBm is passed through the first attenuator. The first attenuator has a gain of 1. The second attenuator has 20 dB output. Find the dBm and watts This is what I tried ...
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2answers
68 views

How is the solution for \$\alpha\$ and \$\beta\$ current gain of a BJT derived?

I'm just an enthusiast, and not too good at maths; I'm exploring constant current source circuits, in doing so I came across two equations for BJT current gain: Could someone help me understand how ...
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1answer
58 views

Quick question about a closed loop control system

Using above loop, we see that \$ \dfrac{y(s)}{r(s)} = \dfrac{p(s)c(s)}{1+p(s)c(s)} \$ and \$ \dfrac{e(s)}{r(s)} = \dfrac{1}{1+p(s)c(s)} \$ (well known results) Why is that: If the close loop ...
-4
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1answer
54 views

Good book references for physics and math for electronics [closed]

Next year I'll join an engineer school in Dijon, France in the field of Electronics (Embedded Systems). I am currently taking a 2 years general IT education and my main problem is that I am very bad ...
0
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1answer
34 views

Simple problem with phasors

I'm trying to solve the following question (a): According to the solutions manual and wolfram the answer is: ...
2
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2answers
100 views

Why is this second order system difficult to control?

Why is system of the type $$T = 1/(s^2 - 1)$$ Difficult to control using standard control methods? When I look at frequency plots, it doesn't seem to give me any important information as to why ...
1
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1answer
63 views

Function to Simulate Realistic Waveform

I need to simulate a realistic signal voltage triangle waveform in Mathematica. I know that a real waveform won't have sharp corners, but I don't remember exactly what a real triangle wave looks ...
5
votes
2answers
110 views

Control theory: is there any actual application for D in ABCD matrix?

Recall that a LTI state space of a dynamical system is given as: Is there any actual purpose for D in the output equation? If D was not zero, it would mean that the output is "directly" ...
0
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1answer
124 views

How to calculate capacitance and resistance for this simple A.M. radio?

\$v_i\$ is the A.M. signal, \$v_o\$ is the modulation wave. How do I calculate the optimal capacitance and resistance, for a given carrier wave frequency? If there isn't necessarily an "optimal" ...
0
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2answers
186 views

Designing voltage summer without op-amp

The above circuit is from Operational Amplifier Adder. Now remove feedback resistor and op-amp, and get the output. From the answer of the question, I know how the end result for Vout would be, ...
0
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1answer
127 views

How calculate standard deviation of ADC histogram for rms noise analysis?

Some papers from Analog Devices (like this one - page 2) and other sources indicates that the rms noise of a histogram plot of an ADC output can be found by calculating the standard deviation of the ...
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3answers
208 views

Collector current vs. temperature

In The Art of Electronics 2nd Ed. it is said that: The Ebers-Moll equation is $$I \approx I_s(T) e^{\frac{V}{25 \, mV}}$$ and the change of voltage with temperature at constant current is $$\left. ...
1
vote
1answer
371 views

Is there a way to Divide two 8 bit number in PIC 18fXXX assembly language not C?

I Can easily do the division in C of PIC micro controller. But is there a way to divide two number stored in two 8 bit registers. For example look at this code. I have to do it in PIC assembly for 8 ...
0
votes
2answers
69 views

Control: what is the proper justification that you can't just make the output equal to the input if the system produces unstable output

Suppose we have a signal, it goes into the plant and generates an unstable response, a common question then arise at that point is why can't we just set our output to a "hard-coded" input. Think of ...
1
vote
3answers
85 views

How can the FFT analyze a wave in which the components are changing?

Based on what I've read about Fourier Transforms, it seems that they are designed to work on waves whose components are constant. For example, a simple square wave is \$\sin(\theta) + ...
1
vote
1answer
97 views

Distinguishing between FIR and IIR filters from transform function

I was good at this but unfortunately I have forgot almost everything... So the question is what are the steps to tell if a transform function is for IIR or FIR filter: $$H(z) = ...
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2answers
810 views

Positive feedback and virtual short in Operational Amplifiers

Can anyone please explain, with sufficient mathematics, why the virtual short concept is not applicable to an operational amplifier in positive feedback.
0
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1answer
80 views

Return Loss \$ (S_{11}) \$ Equation for a nth-order Butterworth Filter

I need a closed form equation for the return loss \$ ~S_{11}~\$ of an n-th order Butterworth low-pass prototype filter. I am designing a high power RF (lumped element) n-th order Butterworth bandpass ...
0
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1answer
123 views

So how do control engineers control nonlinear plant with exponential output?

Say that a system (circuit, pump, population model, etc.) has a exponential output of the type $$y = ae^{bx}$$ What do control engineers do in order to achieve control objectives such as tracking and ...
2
votes
2answers
735 views

Low Voltage AC Smoothing Capacitor Calculation

I have a 9V AC source which will have a max load of 100mA. I'm trying to figure the value of a smoothing capacitor with less than a 10% ripple. I don't have a scope or else I'd just try a bunch out. ...
0
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1answer
40 views

Complex multiplication identity

From my EM theory book: I have the solution for this problem, but I don't even understand the first step. How does V = r+jx => v(t) = rcos(wt) - xsin(wt)??
0
votes
1answer
79 views

Control Engineering: Model parameter estimation for a motor which will be under various loads

I am creating a closed loop controller for a motor which is part of a robotic arm. I give it a required angle, the controller calculates a control input, the motor moves, a pot feedbacks the angle, ...
1
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1answer
145 views

Control Engineering: Why are the Equation Error and Output Error different?

When modelling a system you must first estimate the form of the transfer function (order, time delay etc.), and then estimate the parameters (coefficients for the transfer function). A common way to ...
5
votes
2answers
116 views

How come you cannot determine the capacitance of a MOSFET gate based on the other supplied values on the datasheet?

Conjecture If it's the case that $$ Cg = {Qg \over Vg} $$ It must be the case that $$ (Ciss + Coss + Crss)Vg = Qgon $$ But it turns out that it is not. I don't understand what I'm missing. I ...
3
votes
1answer
173 views

Half Adder and Two Function, A Contest Questions?

I ran into a 2013 contest question on computer-science filed. What is the following True about F and G function. (The output ...
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2answers
96 views

Required math for setting up a laser diode

I'm new to electronics and come from a software background. Recently I got a laser diode that I would like to use with my arduino. The manufacturer says it is 5mW and draws 2.8-5.2V. I'd like to ...
3
votes
1answer
281 views

adding two 64-bits number with m-bit carry ripple adder and multiplexer, a questions?

I ran into a question from computer architecture class. The professor says that for adding two 64-bit numbers A and B we use m-bit carry ripple adders and multiplexers such as following: and that ...
0
votes
2answers
361 views

Understanding use of accelerometers to measure angular (rotational?) accelerataion

Imagine this: A rod is attached at one end to a rotating shaft. So, as the shaft rotates from 0 to 90 degrees back-and-forth (in the xy plane), so does the rod. My goal is to measure the instantaneous ...
2
votes
2answers
719 views

How do electrical engineers actually apply control theory in real life?

I am currently taking a course in control theory. In control theory the system or impulse response is usually an algebraic expression in Laplace domain. Much of the work done in school is to find ...
0
votes
1answer
238 views

Calculating the gauge of wire required for the secondary in a Tesla Coil

I am looking to build a small Tesla Coil at home with limited supplies. I am reasonably confident (well.. as confident as a biologist can be!) with my calculations so far, however I have hit a mental ...
-1
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1answer
55 views

Just need to check if this equation correspond to this block diagram

$$y(n)=y(n-1)-ax(n-1)$$ Is this correct? Thanks in advance.
0
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1answer
59 views

Uncertainity Calculation

> How can i calculate the absolute uncertainty dt in the following case T=(P/A)^1/4 if ...
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2answers
778 views

Question about the derivation of RC Filters frequency cutoff

We've learned that the operation in RC filters depends on how the capacitor reacts to different frequencies, in other words, the capacitative reactance. The input is applied in series with a ...
1
vote
1answer
355 views

Why does the complex representation of a voltage \$V\cdot\cos(\omega t + \phi)\$ use the cosine function?

A voltage across a circuit component at time \$t\$ can be calculated by \$V\cdot\sin(\omega t + \phi)\$. However, in the section of my book that introduces complex numbers to represent voltages, it ...
1
vote
1answer
1k views

Calculating single phase load from 3 phase power measurements

I need to record kW & kWh for individual phases on a circuit that has a 3 phase power meter that outputs the following data: Total for all three phases: kW kWh kVA kVAr power factor ...
4
votes
1answer
278 views

Understanding The Art of Electronics mathematical explanation for capacitors

The author mentions that the reader should not worry if they cannot keep up with the mathematics, I however feel uncomfortable doing so. The issue is the fact that the author does not explain what the ...
0
votes
1answer
186 views

What is the LCCDE equation of this block diagram

I cant find the LCCDE equation of this system ı try to reduce but thing will get compliceted
2
votes
1answer
258 views

Memristor equations

I was working with memristors and wondering about their equations. If the memristor resistance(or memristance) is based on the amount of charge, the memristance should equal: $$M(t)=\int(C(t))dt$$ or ...
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vote
2answers
272 views

Is the cut-off frequency for each high order butterworth filter the same or different?

From reading I see that I can calculate my cut-off frequency for a given Butterworth filter using the equations below. Let's say then that I have a 8th order filter, and I'm going to make it out of ...
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2answers
184 views

High Order Butterworth Filter Math

I'm trying to learn more about high order filter design, with my goal being to design an 8th order Butterworth lowpass filter in spice, then in the real world. I've been reading a filter book I have ...
0
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1answer
97 views

Time domain of a Sine wave?

I am working on a lab in school with a common source JFET amplifier, and I needed to express \$v_{out}\$ in terms of time domain. If \$f\$ is the frequency and \$T\$ is the period, then I need ...
0
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2answers
156 views

How does Decimal Mode in an ALU work?

Trying to wrap my head around the basic of how to do decimal addition in an ALU. Here is what I have so far. I am primarily looking at the MOS 6502 CPU architecture. It has two modes in which you ...
2
votes
2answers
416 views

How do you do operations on large numbers using a small fixed-width ALU?

I am wanting to design a simple calculator like what you would find in the dollar store. Something like this: This little guy can display a number 8 digits long, meaning 99999999 is the largest ...