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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21 views

What is the axial temperature distribution for a electric heating tube

Is the axial temperature distribution uniform for a simple and cheap electric heating element such as shorturl.at/tEJSU I understand that the current that is passed is same along the tube but not sure ...
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1answer
30 views

Is a geared motor better for a DIY wind turbine?

I have decent electronic understanding, but I've not much idea about motors. I plan to make a small wind mill which should be enough to power a couple of LED lights for like an hour every day. I was ...
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light emitting diode matrix [closed]

This is more of a theoretical question, I'm sorry if I do not belong here. I am having a hard time finding technical, theoretical information about LED matrix displays such as when were they invented, ...
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2answers
39 views

Where does the energy stored in a capacitor come from?

My textbook reads, “the power supply does work on the electrons, so their potential energy increases. You recover this energy when you discharge the capacitor.” I don’t get why this is the case... ...
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7 views

Monitoring Connectivity on ZigBee

I am trying to figure out some ways in which a ZigBee network can be monitored. As is the case in any network, here we have a central coordinator and several slaves joined, however, there seems to be ...
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14 views

How to calculate emi shielding effectiveness of a copper mesh?

How to calculate emi shielding effectiveness of a copper mesh, made of wire of dia d, square holes of length s, against an emw of frequency f? Assume mesh to be infinitely long and infinitely wide. ...
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1answer
27 views

Is having one large motor more efficient than having two motors half the size?

I wanted to use multiple smaller motors to have the same strength as a large motor but spread out across a wider area. Is that as good as one large motor or is there some efficiency or power loss in ...
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12 views

Is it possible for UV-C LED irradiation to pass through thin PTFE tubing?

would it be possible that the UVC LEd irradiation can pass through PTFE tubing?
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1answer
15 views

Connect LED with a 0.25mm fiber optic

I want to connect an LED (940nm signal) to a 0.25mm fiber optic. I have researched some possibilities, which involves using shrink heat tube, which is unfortunatly too large or simply buy couplers. I ...
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31 views

Why does my motor model match the actual data in transient but not steady state response?

I have created a model of a DC Servo motor using electromechanical system modeling. I simulated the motor in Simulink (MATLAB) and compared the data with data obtained from a real motor having similar ...
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1answer
39 views

Building oscillating magnetic field circuit

I wanted to create an oscillating magnetic field using an electromagnet which is rated for 12V continuous duty. I was thinking that I need an arduino to control the electromagnetic circuit by using a ...
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1answer
22 views

AC voltage b/w DC power supply o/p and Ground

I have various Phoenix Contact Mini DC Power supply units (Pheonix Contact MINI-PS-100-240AC-5DC). It gives the correct DC Voltage across output terminals, as its supposed to. But I also noticed that ...
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14 views

What effect does energy stored in a capacitor would have on the current it supplies?

For instance, if I take a 0.5 joule capacitor and 1.0 joule capacitor, what would be the difference in currents supplied by the capacitors?
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Can UVC from LED light source pass through PTFE Teflon?

I am looking for a suitable material for UVC light from LED source to pass through. I think Teflon will pass short wave UV but I am not sure.
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3answers
55 views

Bandwidth vs Capacity

Two questions on wireless transmission, packed into one. First: I am confused about the meaning of the term 'Bandwidth' in a wireless transmission environment. The two most common definitions I could ...
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2answers
39 views

Is it a good method to reduce electricity bill

It has become too hot to switch off the air-conditioners.So I read somewhere the aircons works better in higher humidity than dry air because it said AC compresses humidity which takes out the heat ...
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29 views

Pspice ac sweep problem

I want to run an AC sweep from 1 Hz - 10 MHz and calculate the output of the circuit (the voltage on RL), however spice shows that my voltage is 0 in a lot of parts that it shouldn't. I believe the ...
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14 views

What is the purpose of the RG10MEG Resistor in this circuit?

What is the purpose of the RG10MEG Resistor in this circuit? Why is it there, I can't see any difference in the simulation when it's missing. PS: U_IN = 3V DC + 1.5V sinusoidal at 1kHz
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1answer
26 views

Wire with ability to “boost” electron current, benefits to signal propagation?

A wire that can "boost" its signal with electrons fed into it along the way, is it in any way able to propagate a signal further, than a wire that had to feed all its current into it at the beginning? ...
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1answer
28 views

Is 260 picoampere current sufficient to transmit a signal through a 1 micron diameter wire?

This is a question about scale. A normal household runs on 100 ampere, a lightbulb on 1 ampere. Nanoampere is a billion times less, picoampere a trillion times less. When building machines at the ...
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1answer
17 views

Does AC consume more electricity if it is showing less current?

A air conditioner has label 9 amp of current and 2000 Watt. But in actual reading it is showing 7 amp.(may be due to any fault, i.e. low Gas in compressor) Does it consume more electricity or less ...
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1answer
23 views

More voltage through USB ports

What I want to build: So I have an AMD Wraith cooler. And I want to put it on my desk. I managed to connect the coolers power input (12v fan header) to an USB port. And it runs on 5V. I don't want ...
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2answers
70 views

Is there well known equation (formula) to calculate maximum practical current which copper wire of fixed diameter can handle

I found many online calculators or tables which can give maximum current for the wire. Like 1 mm diameter can handle up to 10 Amperes, 2 mm diameter wire can handle up to 30 Amperes, etc. Is there ...
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18 views

Wind tunnel smoke generator

I need some sort of a smoke generator for a small wind tunnel. I have been thinking of making a system that pumps smoke fluid trough a small metal tube wand which has a heating coil at the end of it ...
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1answer
48 views

Understanding the total energy in a AA battery

AA batteries have about 4 watt-hours (14400 joules, 10620.9 pound-feet). Ignoring losses, does that mean a AA battery could theoretically lift 10,620.9 pounds, 1 foot high? You'd need an electric ...
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1answer
21 views

Why do most BMS systems for li-ions and li-pos stop discharging at 2.5V? Are there better systems or is this the standard

From what i've read online, 3.0V is the absolute maximum li-ion and li-po batteries should be discharged and around 3.2-3.4 is preferable for preserving battery life. if that is the case, then why is ...
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1answer
59 views

Could a Jacob's Ladder produce enough hot air for a hot air balloon?

I am curious to know if a Jacob's Ladder would produce enough hot air to keep a hot air balloon afloat, or in other words, that it could be a substitute for a standard gas burner used for hot air ...
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1answer
104 views

linearizing a non linear state space equation

I have this 1-DOF helicopter simulator. The motor's armature resistance is $R$, inductance $L$ and motor constant $K$ and reaction torque on the motor shaft is $τ$. $T$ is equal to $k_1w_2^2$ and $...
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1answer
35 views

Need help with reverse engineering a sensor

I have a pressure/temperature sensor for a vehicle, which I decided to tear apart to see exactly how the sensor works. This sensor as designed by the manufacturer it is meant to be immersed in oil to ...
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1answer
21 views

Design of a hydrogen and corrosion sensor query

I’m designing a hydrogen and corrosion sensor. A thin film changes resistance based on hydrogen concentration. Then the capacitance between two electrodes will change depending on substrate thickness (...
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0answers
21 views

WEC linear inputs

I have seen some designs being made for linear generators for WEC(wave energy) applications. A buoy driving a shaft. But what if the shaft inside was a rack and pinion? If you converted the ...
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1answer
9 views

Melt plastic powder bed with radiant heat?

I want to melt a bed of plastic powder so that the powder bed once melted and then cooled forms a solid sheet of plastic. In order to melt the powder I'm thinking of passing a nichrome (Ni80/Cr20) ...
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5answers
2k views

How do electric companies supply electricity to homes in countries where energy is privatized?

Before I start, sorry if this doesn't make sense English is not my first language. In my country electricity is nationalized so there is only one energy company and one grid. When you build new ...
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4answers
102 views

When an elevator has two buttons next to it, ^ and v, what do they actually mean?

Both as a kid and as an adult, I've encountered elevators lined up next to each other, or single ones, which have two buttons on each floor (outside of the elevator): ...
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1answer
57 views

Running a well pump rated for 230V on 208V power

I have a well with a 1.5 HP pump. The pump is rated for 240V input. At the moment, the only nearby available power is 4-wire 208Y 3phase. I am considering connecting two of the three phases to the ...
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1answer
38 views

how to determine how much speed a motor will produce under load?

I am working on a one-wheel project, I would like to use an electric go kart motor chain driven to a 30 cm diameter wheel and get 90 kg at least 13 m/s with an acceleration of 3 m/s2, I ...
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4answers
45k views

Why do color TVs make black and white snow?

If you let a color TV display something from an unplugged display port, it displays snow, right? Randomly varying black or white pixels on the whole screen. My guess was that the television was ...
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2answers
91 views

What are these outdoors “mystery boxes” for in the USA?

While watching random videos shot in the USA (in the present time), I've noticed these little weird outdoors boxes: What is the purpose of these? They look like they might be related to ventilation ...
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2answers
44 views

Chemical engineering equivalancy to the spring-mass-damper/RLC circuit

I understand the equivalency between the MSD and RLC circuits. Mass ~ resistance, spring ~ inductor, damper ~ capacitor. With the equations of the form MSD: $$ m\ddot{x} + c\dot{x}+ kx = F $$ ...
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24 views

Wobbling DC motor head

I have used 250 watt DC motor, for DIY electric potters wheel. Motor rated with RPM 3300 and geared reduction to 330 RPM. The issue I am facing is wobbling of the motor head. This issue is with the ...
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1answer
52 views

What motor torque specs that is suited for a horizontal to vertical 90 degree lift?

I have this simple design to lift an access door, but I am looking for the motor specs to do this heavy duty job. This is a simple design, I have added some information of the time, length of the part ...
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0answers
23 views

Best way to go about “HiPot” testing setup

What is the best way to set up a dielectric strength test? I am planning on using two threaded copper rods for adjustable movement that will receive the voltage. In between the two rods will be the ...
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1answer
27 views

How to predict out wavelength emitted from gasses

I'm trying to figure out which gas emits a specific wavelength when excited. Say I want to develop an LED that emits a certain wavelength. How would I figure out which gas emits that specific ...
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4answers
95 views

How do you create a negative and positive voltage(-6V and 6V) with a singular voltage source?

I'm trying to use a battery to activate an op amp schmitt trigger but learned that there needs to be both a positive and negative voltage supplied to Vcc+ and Vcc-. I've seen a lot of schematics ...
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5answers
99 views

What sensors/methods can be used from the roadside to determine if a truck is loaded or empty - without weighing it?

What sensor, using what physical principle, can penetrate a closed rectangular object like the trailer of a truck and tell if the space is empty or loaded? Why is this question relevant? One of the ...
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1answer
24 views

Bar heater operating on a duty cycle - possible problems?

It's easy to obtain a room-scale radiant heater (of the order of 700-800W per bar, eg this three-bar heater) that operates very simply and easily - you turn it on, it consumes electricity, it ...
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1answer
40 views

Heating tape that has leads like picture below

Does anyone know where I can find Heating tape that has these same leads or know what they are called? It is meant to be plugged into the second picture attatched.
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3answers
36 views

Design Input: Rotary motion to Linear motion, What system should I choose?

I am posting this here because of the multidisciplinary knowledge needed to tackle this issue. Problem: I have to make an electromechanical device that is required to have controllable (downward) ...
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2answers
55 views

can base current be far less than collector current?

I'm using an NPN transistor to pull the gate of a P-channel FET low. I'm driving the base with 3.3v and a 10k series resistor. I have a 100k resistor in series with the collector and the gate of the P-...
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1answer
24 views

How is the most basic display driven?

I am curious how taking the most basic display such as this OLED one that works with the ardunio is driven: i.e. We are using just a clock and data line to drive a 128x64 pixel display. The pixels ...

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