Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [math]

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

2
votes
0answers
22 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 ...
0
votes
1answer
60 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 ...
0
votes
1answer
54 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/ ...
0
votes
1answer
36 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 ...
0
votes
2answers
51 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 ...
0
votes
2answers
67 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}{...
1
vote
2answers
90 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(...
-1
votes
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 ...
0
votes
4answers
92 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 ...
0
votes
0answers
47 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 ...
0
votes
2answers
60 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 ...
1
vote
1answer
43 views

Explanation of 5 Parameter Model for Solar Cells

I am having a hard time understanding this equation, the 5 Parameter model for photovoltaic cells. \$I = I_{ph} - I_o[\exp(\frac{V + R_sI}{nV_t})-1] - (\frac{V+R_sI}{R_{sh}})\$ My goal is to apply a ...
-6
votes
1answer
54 views

How to calculate the transmission distance from satellite to earth (How to understand the formula) [closed]

I have this question in one of my tutorials and I cannot seem to find clarity in the question - I am trying to make an algorithm to do this all automatically but I need to understand the formula I ...
0
votes
0answers
47 views

RLC circuit with intial conditions

The circuit I have is given by the following schematic: simulate this circuit – Schematic created using CircuitLab I know a few things: The current in the circuit at \$t=0\$ equals \$\text{I}...
0
votes
2answers
88 views

Connecting the following structure of multipliers and adders in an elegant way in verilog

I am attempting to write a synthesizable verilog (or Systemverilog) module. I also want to make the modul parameterizable, which has presented a problem when trying to connect the following structure ...
1
vote
1answer
64 views

Compensate centrifugal force in accelerometer measurements

I'm working on a project that includes counting the revolutions of a cylinder connected to an engine. This engine runs at a minimum of 5 revolution per second and a maximum of 9 revolution per second. ...
1
vote
0answers
41 views

How do you calculate average absolute value of a sum of sin functions with different amplitudes and frequencies?

I cant seem to find the answer anywhere. I remember there was a simple formula for doing this but I dont have the book with it anymore. Finding where the function is positive and where is negative and ...
0
votes
2answers
117 views

Conversion from dBm to dB\$\mu\$V?

I am trying to derive the conversion from dBm to dB\$\mu\$V. So, please correct me If I am wrong. \begin{align} \textrm{dBm} &= 10 \log_{10} \left( \frac{P}{1\textrm{mW}} \right) = 10 \log(P) + ...
0
votes
1answer
92 views

Convert ADC value to real voltage

I want to measure the input voltage to my circuit. The input voltage is supposed to be anything between 7 to 35 Volts. I have a micro-controller with 12bit ADC. I am using a simple voltage divider to ...
0
votes
1answer
783 views

Calculate battery state of charge percentage

What is the correct formula to calculate battery state of charge percentage based on the battery type (12v, 24v, 48v and so on) and the current battery voltage. For example if I have a 12v battery ...
4
votes
3answers
143 views

Order of precedence for parallel operator

In electrical engineering the parallel operator || gives half the harmonic mean of two values. E.g.: \$R_1 \parallel R_2 \equiv \frac{1}{1/R_1+1/R_2} \$ But how should you compute \$kR_1 \...
0
votes
1answer
67 views

Control Theory Integrator Phase Shift

Guess I should know the answer, but I can't come up with a good explanation. I always have to remember which sign cos and sin have after integration/differentiation. I usually do this by thinking of ...
0
votes
1answer
47 views

Finding current over controllable voltage source using nodal analysis

I have the following circuit: Let me explain the diagram a bit first: I0 is current in that direction, V0 is voltage and 2 V0 is also voltage times two. V1, V2, and V3 are my nodes. The 'S' by the ...
29
votes
5answers
13k views

Why is the time constant 63.2% and not 50% or 70%?

I am studying about RC and RL circuits. Why is the time constant equal to 63.2% of the output voltage? Why is it defined as 63% and not any other value? Does a circuit start working at 63% of output ...
1
vote
1answer
66 views

Finding the fourier series coefficients of the signal $$1+\sin (\omega_0 t) + \cos (\omega_0 t) + \cos (2\omega_0 t + \pi / 4) $$

I have come across this question that asks to find Fourier series coefficients of the following signal. $$1+\sin (\omega_0 t) + \cos (\omega_0 t) + \cos (2\omega_0 t + \pi / 4) $$ In my intuition, ...
0
votes
1answer
60 views

Control Theorie: Drawing Transition Matrix Trajectories

Given a transition matrix like e.g. $$ \phi(t)=\begin{bmatrix} e^{-3t} & 0 \\ 0 & e^{-3t} \end{bmatrix} $$ What is the analytical way of drawing x(t) for two given starting points? I only ...
0
votes
1answer
50 views

Multi phase vs single phase power factors

Are there any differences between calculating single phase and multi phase power factors? I'm open to general answers, but more specifically: If PF1=P/S, does PF3=(Pa+Pb+Pc)/(Sa+Sb+Sc)? Does ...
0
votes
1answer
40 views

2D Positioning Localization

I have a robot. My robot has three main sensors one is a gyro from which i can get my yaw, pitch, and roll. I also have an encoder in the x and y axis. How can I use these sensors together to reliably ...
2
votes
2answers
74 views

In a Wilson mirror, does Q3 need to have the same beta to cancel the base current error?

I'm learning about Wilson mirrors in the Art of Electronics Third Edition (pg. 102). It shows the following circuit: simulate this circuit – Schematic created using CircuitLab It then ...
0
votes
0answers
27 views

Find vertical shock from IMU during inclination

The PCB can be mounted in any orientation and from this the firmware must calculate the vertical shock that it experiences. As it would be calculation intensive to calculate he vertical shock for ...
1
vote
0answers
66 views

Calculation of Euler angles. But gets a change (delta) in change and not a constant value

What I've done will now: I'm using an IMU (MPU6000) to calculate the Euler angles of an object and for this, I'm using Madgwick AHRS algorithm. The MPU gives acceleration due to gravity (a) about the ...
0
votes
1answer
42 views

What's oscillatory instability in the delay differential equations?

Does DDE’s stability depend on forcing term and ODE’s stability does not depend?If yes, then is frequency analysis of stability applicable only to DDE and not ODE? In control systems, we study ...
0
votes
2answers
125 views

Poles and Zeros of Two Pole Compensation

I am known with the basics of what poles and zeros of transfer function are and how to determine them, but I certainly don't know how to apply such poles and zeros to the gain curve, which describes ...
4
votes
5answers
154 views

Average of a periodic voltage

I know that this question is math related, but I still don't get why we can say the following formula holds: I've a voltage \$V:\left[0,\infty\right]\to\mathbb{R}\$ and \$V\$ is periodic with \$T\$....
0
votes
1answer
97 views

Digital Multiplication, Subtraction, Division Integrated Circuits?

Having a hell of a time finding ICs that offer multiplication, subtraction and division? Are these functions just a product of adders and not worth the fab?
0
votes
0answers
29 views

Finding root mean square of a periodic function with transient phenomenon

I've a electronic signal that is periodic after some time. Let's say in the first \$n\$ seconds the (transient phenomenon) can be described my the function \$f(t)\$ (for \$0\le t<n\$) and after ...
0
votes
0answers
57 views

Roll-off of a third-order active filter [duplicate]

I've a third order active filter, without zeros. I know that when \$f=0\$ the gain response is \$1\$. So the cutoff-frequency is located at: $$\left|\text{H}\left(\omega_0\right)\right|=\frac{1}{\...
2
votes
2answers
331 views

Roll-off of a filter

I know that the roll-off of a transfer function gain is given by: $$20\log_{10}\left(\left|\text{H}\left(\omega_2\right)\right|\right)-20\log_{10}\left(\left|\text{H}\left(\omega_1\right)\right|\...
1
vote
1answer
41 views

Why do the brightness, luminous efficacy and power of this lightbulb not agree?

A particular LED lightbulb has luminous flux (brightness) \$\Phi_{\rm v}=820\ \rm lm\$, consumes electrical energy at a rate of \$P=9\ \rm W\$, and has a luminous efficacy of \$\eta=83\ \rm lm/W\$. ...
1
vote
2answers
454 views

Role of complex number in electronics [duplicate]

Complex numbers contain imaginary numbers as we all know but often it is used for solving real life practical problems such as taking the impedance of a capacitor, inductor etc. Even in Signals and ...
1
vote
2answers
161 views

Does the resistor values used for opamp circuits come from the equations?

I've the following circuit: I used the LM741 as the opamp. The input resistance is \$2\cdot10^6\space\Omega\$, the output resistance is \$75\space\Omega\$ and the voltage gain is \$2\cdot10^5\$. ...
0
votes
1answer
205 views

RC step response equation derivation

So this isn't really a big question, but I really need to get something clarified from the derivation of the RC step response equation, which goes like this: $$V(t)=V_S+(V_0-V_S)e^{-\frac{t}{RC}}$$ ...
0
votes
0answers
48 views

Determine the frequency and on time of two coupled ne555

I've the following circuit: I use it as a voltage controlled pwm generator. My question is, how can I find the frequency and on time of the PWM. I tried changing all the resistor and capacitor values ...
1
vote
2answers
333 views

Current Consumption of ICs from Datasheets

newbie in electronics here and taking self study (don't have time to go to school anymore xD). i just want to ask, regarding the image below: it came from this datasheet: https://d3uzseaevmutz1....
3
votes
2answers
71 views

Why did my textbook use signal energy as a measurement of approximation error, instead of something else?

TL,WR: Why do we use signal energy as a measurement of an approximation's error, and not something "simpler" like the absolute value of the error? Background: I'm reading through my textbook for my ...
0
votes
1answer
3k views

Nichrome wire gauge calculation

I know what battery I wish to use (3.7 V 140 mAh which I can swap for larger mAh battery) I know what length of wire (3.5 inches or 7 inches depending on which ever would work better) I know what ...
1
vote
1answer
73 views

Question about the RMS value of the real input power

I've the following circuit: simulate this circuit – Schematic created using CircuitLab I know that the relation between the input voltage and the input current is given by: $$\begin{cases} \...
12
votes
7answers
3k views

Acceleration when device is on tilt

I'm currently working on device that uses always-on 3D accelerometer(using scale +-2g) and 3D gyroscope(using scale +-250g) -sensor. I can read every possible vector (X,Y,Z) and their acceleration (g'...
2
votes
1answer
175 views

LC circuit with series diode (finding the linear average)

I've the following series LC circuit: Find the (linear) average of the current trough the diode. The ideal is a ideal component. The initial conditions in the circuit are equal to zero. MY ...
1
vote
2answers
89 views

Electric Field electrical charge

Hey i dont know how to solve this. Can somebody help me? In the two-plate arrangement shown in the sketch, there is homogeneous electrical field strength $$\vec{E_0} = -\vec{e}_y * 10\frac{kV}{cm}$$ ...