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

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Simulating accelerometer noise

I would like to create a software simulation of an accelerometer (MPU-6000). As part of that simulation, I need to model the noise on the accelerometer signal. According to the datasheet of the chip, ...
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1answer
45 views

Converting a summation to an integration

I've seen it done a few times, it's always roughly apparent that "oh yeah, okay, they've dropped this, pulled this there, yeah, okay, kind of convincing" - but I've never why or how to do it for ...
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1answer
55 views

Number of independent KVL equations in a circuit?

Could someone explain why, for a circuit with B branches and N nodes, the number of of linearly independent KVL equations for a network is: B-N+1 Thanks.
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7answers
413 views

How do we know loop currents exist?

I've been practising loop analysis questions, but don't really understand why the method is valid. Say you have a circuit that only consists of resistors and some power source. Assume the circuit is ...
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3answers
83 views

Why are the Resistance/Resistivity Equations Formulated as they are?

The equation for temperature dependence on resistivity: $$ \rho(dT) = \rho(0)(1+\alpha dT) $$ where \$dT\$ is change in temperature from some reference and \$rho\$ is resistivity. This leads to ...
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1answer
75 views

Frame size range calculation for stop-and-wait protocol

I have a question and answer below. The answer seems to show less working on how it derived. My question is if the efficiency of at least is changed to say 60%? Will it still be the same answer? ...
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1answer
82 views

To what extent can Gielis' so-called “Superformula” be used to improve the efficiency of WIFI antennas? [closed]

I am new to this Stack Exchange venue, so please don't shoot me if this question is not appropriate. This question was taken Math Stack Exchange. In 2003, the Belgian plant biotechnologist Johan ...
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3answers
363 views

How long can I practically power an IC with a capacitor?

If I have, for example, an IC that draws 10mA @ 3.3V, how large of a capacitor would I need to power it for 2 minutes? 5 minutes? I understand that using capacitors to power an IC is not the most ...
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0answers
83 views

Understanding how bypass caps work, mathematically

Assume there is a band of noises that you you want to filter with center frequency Fn. Then The complex voltage representing noise at frequency F is V_(F, T) = V(F) e^(i W(F) T), where V(F) is the ...
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1answer
74 views

Is there a convention for the polarity of voltage specified as \$V_{XY}\$? [duplicate]

Inspired by this answer, which includes the image: Which solicited the comment: No, you have the polarity of Vce shown backwards in the diagram [...] The diagram seems consistent to me: the ...
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2answers
53 views

Are there other uses for the value of RMS current besides heating computations?

For most purposes I've personally encountered, RMS current and voltage have been useful only for computing heat losses in a resistor. Do RMS current or voltage have other applications besides ...
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4answers
859 views

Mathematical proof that RMS voltage times RMS current gives mean power

I know this is true because I read it in a reputable source. I also understand intuitively that power is proportional to the square of voltage or current for a resistive load, and that the "S" in RMS ...
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1answer
158 views

Tracking 2D positioning with IMU Sensor

I am using a miniature car and I want to estimate the position. We can not use GPS modules and most of the tracking systems that I saw, are using IMU senson with the GPS module. In our car we are able ...
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3answers
93 views

How do I size fuses to handle sudden changes in AC line voltage into a capacitive load?

Suppose I have a rectifier on the AC line, followed by some caps and a load. simulate this circuit – Schematic created using CircuitLab If the AC line is suddenly increased, there's a ...
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1answer
113 views

Capacitor discharge math discrepancy

I'm trying to cross check mathematically the mA being discharged from a .33uF capacitor which is charged to about 1200V by a circuit which is provided 37W of power to it. I do it three ways. 1) ...
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1answer
140 views

What is the fastest logic gate?

I have been told that the fastest logic gate family is ECL. My first question: Is this true? In this or another family (Depending on the answer to the above question), Is there any particular gate ...
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1answer
90 views

Affine Non Autonomous State Space system

Normally We all know the state space model of the the form der(x) = F*x(t)+G*u(t) y = H*x(t)+J*u(t). However I came across a state space model which has the following form der(x) = F*x(t)+G*u(t) + ...
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1answer
61 views

Z-Transform Initial Value Theorem

I have a small understanding of how to solve limits to infinity for regular rational equations, but I'm unsure of how to apply this to the Z-Transform initial value theorem. The equation is: \$ ...
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2answers
128 views

Average Power Formulas

I've becomes a bit confused with the average power formulas. These formulas can be found on Wikipedia here and here. Let's suppose V(t) = 1V (DC) and we have a square wave for the current that ...
4
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2answers
104 views

Salvage data from a reverse connected thermocouple?

My SAE Baja team had a competition this past weekend, and we were using some thermocouples in order to get some temperature data on the drivetrain and engine. They were hooked up right before the ...
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1answer
213 views

What is the physical meaning of an LC circuit having a negative transfer function?

Say you have an ideal LC circuit: simulate this circuit – Schematic created using CircuitLab The transfer function of this circuit is a complex voltage divider: $$ \frac{\frac{1}{sC}}{sL ...
3
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2answers
242 views

Converting raw temperature data to Celcius L3GD20

I have an L3GD20, which is an accelerometer with a temperature sensor built in, and I want to make sure my math isn't funky regarding the temperature. I'm not exactly experienced with embedded ...
4
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1answer
121 views

Need help interpreting a basic circuit question

In my Nilsson "Electric Circuits, 5th ed" book, there's this drill exercise near the beginning of the book. Here it is: Current at the terminals of the element is t<0: $$ i=0 $$ t>=0: ...
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3answers
165 views

Attempting to determine power consumption

So I am attempting to determine if the battery I choose can power the devices I need. This is my first day doing anything with ohms and current and such. So go easy. I have: 2000mAh battery 45mA ...
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2answers
432 views

Overflow detection in a CSA (Carry-save Adder)

How do you detect overflow when you have a CSA? I have 3 16-bit two's complement inputs and a 16-bit output and I'm wondering how do I detect overflow?
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0answers
74 views

JFET “How to find resistance of the device”

I have this homework question that I can find one way to get the answer but I want to use a certain equation "attached" to find the answer also. I'm having a hard time understanding what to ...
2
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1answer
57 views

How does one compute the ripple currents seen by an active PFC output capacitor?

Suppose one is designing a single-phase power-factor-corrected power supply, with a known average current load: The ripple current seen by the output capacitor is critical. If that current is too ...
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1answer
118 views

Find the peak load of a power plant for the given load equation

The daily load demand of a grid is given by $$P=P_{max} \cdot cos(\pi t/24)$$ Here \$-12hrs ≤ t ≤ 12hrs\$. Maximum power occurs at (\$t=0\$) and minimum occurs at (\$t= ±12\$). A \$10 GW\$ hydro ...
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2answers
531 views

Double-Subscript Notation for Voltages

I have read from some book that: "The voltage quantity symbol V sometimes has subscripts to designate the two points to which the voltage corresponds. If the letter a designates one point and b the ...
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4answers
261 views

Component with an impedance that has a negative real part

Is there an electrical component such that its impedance has a negative real part ? Fact: Any electrical component made from resistors, inductances, capacitors (connected in possibly complex ways ...
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2answers
229 views

ARM Power/Exponential Function

I'm trying to code an exponential function for use on a PWM signal. My question is, does anyone know how to do a power function on an ARM cortex-M (STM32F4 in this case, which has an FPU) ...
0
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2answers
262 views

basic math question about voltage, ohms, resistance

total n00b here. After working on several projects by copy & paste from other people's schematics and code, I'm finally digging in and learning some of the math to know what I'm doing. If I have ...
3
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1answer
148 views

Convert between dBA, dBV and RMS values

How do I convert between dBA, dBV and RMS values? For example, I have used a current probe (clamp) with a gain of 100mV = 1A to measure a series of currents in dB and I would like to know the ...
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2answers
5k views

how to select capacitor values

I am trying to find information on formulas used to calculate capacitance required for a given circuit. Not a circuit in particular, just in general how to figure out what value should be used. I know ...
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2answers
1k views

I have to determine if the signal is linear, time-invariant, and/or causal

Here is my problem: $$\frac{d^2y}{dt^2} + 5\frac{dy}{dt} + 8y(t) = \frac{dx}{dt} + 3x(t)$$ I have to prove if this system is homogeneous and additive in order for the function to be linear, but can ...
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1answer
150 views

what type of electronics job would combine mathematics, electronic design and programming into one [closed]

There are quite a few different areas of jobs in the Electronics industry. We have Analogue, Digital, Embedded, Telecommunications, Control and much more. What I wish to know is that what job would ...
3
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1answer
685 views

Constant current source math - Using AD8276 differential Op-Amp

So I'm trying to implement a constant current source to conduct a specific measurement using a AD8276 differential amplifier. I'm trying got derive the equations my self for sanity check, and to give ...
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3answers
274 views

Solving this op-amp circuit

I would appreciate some help solving the following circuit. I've been trying for a very long time and can't get the same answer the book has. I'm trying to get \$ V_o \$ in terms of \$ I_{os} \$. ...
3
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1answer
199 views

Switches needed in an n-location multiway switching system

Wikipedia shows us we can construct a two location multiway switching system with two 3-way switches: They also teach us how to perform three location multiway switching with two 3-way switches and ...
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2answers
191 views

Basic circuit analysis - diferential equation

This is the circuit I got from an example in a book "Practical Electronics for Inventors", on page 48: How can one understand that \$0=R\frac{dI}{dt}+\frac{1}{C}I\$ implies ...
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1answer
563 views

How does one compute the ripple currents seen by a boost converter output capacitor?

Suppose one is designing a boost converter, with a known maximum current load, and a known inductance: The ripple current seen by the output capacitor is critical. If that current is too high, the ...
5
votes
1answer
924 views

How does one compute the ripple currents seen by a rectifier filter capacitor?

Suppose one is designing a full-wave rectifier bridge, with a known maximum current load, and a known input inductance. Assume three-phase for this example, though the same concept applies to ...
2
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3answers
325 views

Does LTSpice support a “Remainder” or “Modulus” function?

I am trying to change a parameter in LT Spice with if statements and make it change on whether a different value is even or odd. Mathematically, this would be easy with a remainder or modulous ...
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0answers
58 views

Are descriptor systems necessarily non-minimal?

I am working with model order reduction for electrical circuits. I am looking to implement Balanced Truncation as a form of model reduction. The systems I work with are definitely stable, but not ...
3
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2answers
302 views

How to mathematically determine the frequency of a tone based on components being used

My REAL question is how to choose the right components if you want a specific frequency spit out from a 555. In my particular case I want a potentiometer to control an output frequency from 16Hz to ...
3
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1answer
295 views

Addition and subtraction in digital electronics

Why is it that addition of the 2's complement is an efficient method of subtracting? Does this simplify the circuit?
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4answers
2k views

How fast does a 64-bit multiply or divide execute on an FPGA?

When using a regular FPGA such as Xilinx Spartan 3 or Virtex 5, how many cycles does a double-precision floating-point 64-bit multiplication or division take to execute? As far as I understand, the ...
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1answer
154 views

SQNR of 16 bit signed multiplication with MSB storing in 16 bits

I'm trying to figure out what the SQNR is if I multiply 2 16-bit signed integer values and store the result as a 16-bit signed integer, dropping the least significant bits. For example: a (16 bit ...
0
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1answer
106 views

Calculating run time for a device with variable current draw

I recently built a small microcontroller-based project for a friend that consumed different amounts of current at different times. I wanted to calculate the run time for a given battery type (but ...
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3answers
392 views

Can you sum and difference in a single op-amp?

I want to take two independent differential signals (audio line inputs with unknown properties which may be present or not), remove any common-mode noise from each of them (they could each have ...