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Questions tagged [electrical-engineering]

Study and applications of electricity, electronics, and electromagnetism. Use this tag when someone who has trained as an electrical engineer is likely to be able to answer your question.

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1answer
26 views

Why do pitching machines use wheels and not solenoids, actuators, servos or peumatic cylenders?

I guess that generating movement is harder then keeping a wheel rolling, but in terms of power consumption is it possible to compare the power consumption of a motor for driving wheels to that of a ...
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1answer
39 views

How much rain water run off do I need to power an LED greenhouse

My question essentially is how much water to power green house LED lights. Specifics bellow : Say I have a warehouse with a flat roof with a bunch of water tanks or the whole thing being a water tank....
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0answers
27 views

How to obtain transfer function of servo?

I am using a servo motor and controlling it via arduino. Servo motor is part of a control system and I have to use System Identification techniques in order to obtain the servo's transfer function. ...
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1answer
34 views

What is the voltage at the ground electrode of a spark plug?

Since the voltage required to bridge the gap between the central electrode and the ground electrode of a spark plug can reach up to 40 000V and even more, my question is, how does the battery not die ...
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0answers
19 views

P-N junction depletion region

Before I explain my problem I'd like to mention I'm still green and about 2 weeks into these topics. I learned most of it from youtube videos, wikipedia and other science sites, so I'll be explaining ...
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1answer
41 views

Constant force opposing hydraulic winch

I have a situation that I am hoping to solve with the use of electric motors, and a variety of controls. I have a hydraulic winch which turns at speeds from 0-60 RPM. This winch is coiling and ...
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0answers
25 views

small touchscreen for handheld instrument

I'm trying to find a small approx 2.5" touchscreen display that would be good for utilization in a small battery powered handheld instrument that has a frequently updating value that it reads. e-ink/...
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0answers
18 views

Confusion about 2-bit adders

I am a little confused about how a 2-bit adder works. For 1-bit adder, my understanding of it is fine and I am able to draw out the truth table for it. However, if lets say I have a 2-bit adder, I can'...
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0answers
20 views

value of $\gamma$ in the H-infinity norm

Suppose I have the system: $\dot{x} = Ax+Bu$ $y=Cx+Du$ and the following Hamiltonian matrix: $H=\begin{pmatrix} A & \frac{1}{2}B^TB\\ -CC^T&-A \end{pmatrix}$ I want to find the value ...
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1answer
46 views

How to add external sensor data to pictures, canon DSLR, hot shoe, electronics

Here's a challenge - I am trying to add different sensors data (height,temperature,distance by laser) to pictures i take with a canon DSLR camera. Would it be possible to connect different sensors ...
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1answer
36 views

How long do external hard drives and the data they contain last?

How long do external hard drives and the data they contain last in case of lack of any use after downloading the data and the condition of storage having a room temperature, average humidity of 60-70% ...
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0answers
19 views

RC Bandpass Filter on pspice :unity gain frequency

I am simulating a pspice bandpass RC filter by cascading 2 opamps one HP and one LP. I am getting this bode plot at the end. Is the unity gain frequency the 2 frequencies at 0 dB?
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1answer
44 views

Electronic symboles in datasheets

I found these symbols in a electronic datasheet.. Are these all logic gates? or another?
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1answer
13 views

Flat Fading vs Selective fading, which one is better?

I come from Maths background, but recently I encountered problem where a channel is described as "flat fading channel". I would like to make some conclusions based on that fact. I suspect that for ...
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1answer
26 views

Cannot understand an equation related to impedance. (Power system analysis)

Can someone explain how can we find |Z| term and also from where does the cosine term arrive at the final equation.
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0answers
22 views

Please help me with 2-D Dynamic analysis in ANSYS Mechanical APDL

I'm trying to do dynamic analysis of an electric motor using Ansys Mechanical APDL. The stator has 4 pole pairs and only 1 of them has windings. The rotor has 3 pole pairs with no windings. I want to ...
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0answers
62 views

Help with Engineering Mathematics, Struggling to determine coefficients using methods detailed in this research paper

I am struggling with a curve fitting calculation below. the part I am stuck with is arguably the simplest part, which is determining the coefficients $\\K_3$ and $\\K_4$. It seems like it should be ...
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0answers
29 views

Solar power, Battery power to mains voltage

My question is what is the most efficient way to convert 48V D.C. to 220V A.C. Not the easiest or most cost efficient but the most efficient electrically? Also if anyone has any cheats on the best ...
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2answers
39 views

oscillation motion from DC motor (computer fan)

I intend to make an oscillating motion from a simple computer DC fan (say 5V). My question is: could a signal generator with a sinusoidal signal of (say voltage 5V and frequency of 5 Hz) be used to ...
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1answer
42 views

Why are FBG sensors recalibrated every 10 years?

So, I am working with FBG sensors and I have read that those sensors need to be re-calibrated every 10 years to get accurate measurements. But no where on the internet (AFAIK) is it explained why ...
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1answer
57 views

How to drive 12V servo motors using 5V PWM or 3.3V PWM using ARM MCU?

I have to drive several 12V servo motors. So I wanna to get 12V PWM Controller (12V Logic Controller). I have MCU as Atmel SAM3X8E arduino due board. It has 5V PWM outs. Is there any Controller IC ...
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0answers
13 views

74141 BCD-to-decimal converter lighting wrong/multiple LEDs [closed]

I'm having trouble with a 74141 IC while building a nixie clock. At the moment I'm testing it with 10 leds and a 4K7 resistor, expecting them to light up one at a time as per schematic: NTE74141 ...
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1answer
38 views

What's the point of ESD-safe tweezers?

ESD-safe tweezers have a black coating on the handle. If I am grounded to a work bench, and normal tweezers are already conductive, then what is the point of the conductive black coating? Screw ...
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1answer
56 views

Controller vs Micro controller?

We often listen both term in electrical engineering? First one is seen in control systems course and second one in course of embedded systems But what is difference between both of these terms?...
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1answer
27 views

Power/energy density of an actuator

What is the meaning of power/energy density of an actuator? Context: As a novel kind of actuator, the dielectric elastomer ( DE ) demonstrates high-strain response [ 1 ] , high energy densities ( ...
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2answers
60 views

How do trolleybus switches work?

The switches are so high it's not possible to see how they function on the ground. I really tried to look up information about this on the internet, but there's very little info available, and the ...
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0answers
23 views

Is it possible to simulate the electric power output of a linear alternator using finite element analysis software?If yes, which?

We need to build a small (1-2W) linear alternator for a project in engineering school. Is it possible to use finite element software to finetune our design instead of actually building real life ...
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1answer
38 views

How exactly do noise canceling headphones work?

I purchased a pair of noise canceling headphones today and I was just wondering how exactly they are able to cancel out background noise?
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2answers
47 views

not sure how to use a signal from a sensor to make a lightbulb turn on or off

I am a very new student of engineering. I am in high school. The problem is my grandpa has an obsession with checking to see if the garage door is closed. So my dad is trying to get me to develop a ...
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1answer
28 views

How to estimate wind generation using power curve?

I am trying to verify windfarmer generation estimates manually. To do so I am trying to manually calculate the estimated energy production (kWh) of a wind turbine. The information I have available is ...
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0answers
10 views

Forward converter currrent flow

If we have the following forward converter: when $Q_1$ is on we have: Why is it that the Diodes $D_1$ and $D_3$ are off? Similarly when $Q_1$ is off why is Diode $D_2$ off?
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1answer
49 views

Get engine rpm using accelerometer

I'm studying the possibility to read an engine RPM by reading the vibrations of it. Basically an engine is "oscillating" on a car chassis on all 3 axes (X, Y, Z) but mostly on the Y one. When ignition ...
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2answers
33 views

How does ferranti effect occur?

I search and read about Ferranti effect online, but none seems to be clear enough for me to understand how it actually happens. I must say, I do not have much prior knowledge about inductive/...
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3answers
118 views

Relative inefficiency of doorless fridges at supermarkets

It appears to be a waste of electricity to keep a bank of refrigerators wide open with no doors or covers whatsoever on them. They seem to be just blowing cold air out into the supermarket. They ...
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1answer
65 views

How do I determine the temperature inside a transformer vault?

I am trying to determine the temperature of an underground concrete vault buried 10m underground. The vault has the following dimensions: 2640mm x 5995mm x 2640mm with a wall thickness of 250mm. The ...
2
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1answer
93 views

Why does collector current increase with base current in BJT?

The base current in the BJT is due to the recombination of holes and electrons. To neutralize the p region an electron leaves the p region. If we take it the other way round, the larger the base ...
1
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1answer
37 views

How much aluminum does a HV, MV or LV transmission line use?

I have accurate statistics about the total length of high-voltage (110-400 kV), medium-voltage (1-70 kV) and low-voltage (0-1 kV) transmission lines in my country, and they are: High-voltage: 22 500 ...
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0answers
22 views

How would I go about charging titanium dioxide for e-paper technology project?

I'm experimenting with rubbing a balloon on a silk (to get the electrons) and then touching the balloon to two small aluminium foil balls to see if they'll repel but they don't (if I do it with ...
1
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1answer
33 views

Why is the tv playing if the carrier frequencies in our RF project appear unsupported?

My group made an RCA video/audio to RF modulator for a school project. The video is a NTSC composite video signal. Here is a clip of our tv receiving the output of the project on NTSC channel 2: ...
2
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1answer
106 views

Why/when is AC-DC-AC conversion superior to direct AC-AC conversion?

I am currently studying wind power and the power electronics used for it. In wind power a generator is driven by wind, thus the resulting power is of widely varying frequency and amplitude. The power ...
1
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0answers
26 views

Is it possible to calculate torque using strain gauges on a rotating shaft?

I am currently designing a torque sensor and am looking into the ability to use strain gauges as a instrument to measure strain and calculate torque. The current setup is two motors connected via a ...
0
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0answers
34 views

Can e-paper capsules be made larger in size?

Can I buy individual (larger in size) e-paper capsules from somewhere? (for an electronics project for example) and is it even possible for such large e-paper capsules to be engineered?
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0answers
23 views

DC motor Magnetic axis of armature winding vs EMF

When considering the cross section of a DC motor we have: I notice that the Magnetic axis of the armature winding is aligned with direction of the EMF that will cause the rotation. Is there a ...
2
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0answers
25 views

Health hazards of disassembling electronic devices?

I´ve been disassembling a lot of electronic devices in order to recycle them, separating plastics, electronic boards and bolts/other metal parts. Is there any proof of health hazards for doing it ...
2
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0answers
23 views

Mobile Frequency and Carrier Frequency not Matching

I am using a Google Nexus 6 Mobile in India with Airtel as Network Provider. Recently Airtel has upgraded their Network to 2300 Mhz 4G. Whereas Google Nexus 6 Operates on Band 3 (1800Mhz) LTE. When ...
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2answers
34 views

Induction heating rebar in cold weather

An induction cooktop has a high frequency power source that is applied to a coil. I was wondering if you could take the high frequency electronics from a cooktop or even buy / design a high frequency ...
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0answers
32 views

Can I use a single stator coil to actuate/rotate two rotors inside and outside of the stator

I want to design a motor system where a single stator coil is responsible for two rotors of neodymium magnets on its outside and inside, will this work, and what are the downsides I should be ...
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0answers
22 views

How to detect milk spillage or milk boil?

In my country we generally boil milk before we drink. Often the milk heats up and spills from the pot. I want to detect milk boil before it spills off.I am thinking of a thermal camera solution that ...
3
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0answers
36 views

What kind of professional(s) build/design factories? [closed]

I have a small self-built food processing unit (500sqft) but it is very labor-intensive. I want to make a larger unit (45,000sqft) with 100x more output using factory machinery (automation, conveyor ...
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1answer
33 views

What is the type of this connector?

Can someone tell me what the type of connector is??