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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
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Is there a motor design where a rotor gradually moves into a stater?

I was wondering if there is a motor/generator design where the rotor moves gradually in and out of the stator along the axis of rotation, or the stator over the rotor. If so, I'd like some resource(s)...
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1answer
13 views

Hover Stylus for capacitive touchscreen

Capacitive touchscreens do not rely on touch as the name suggests but rather measure the distortion of the electrostatic field. To my understanding a touchscreen might be able depending on the build ...
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0answers
27 views

Second Order OPAMP circuit

I was trying to understand the way this problem was solved and I got confused with the latter part of the solution. I encircled the part that confused me. They seem to contradict each other. If $\...
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2answers
20 views

Why does a lead-compensator type system decrease to a step response

For example, the step response of $\frac{s+1}{s+2}$ is decreasing although its gain is +1, and this system has higher gain at high frequencies than low frequencies based on its Bode plot. But if I ...
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1answer
36 views

What is the appropriate type of controller for this system?

I am given this transfer function for a system: $T\left(s\right)=\frac{9.81}{s^4+0.5s^3+11.2815s^2+4.905s}$ Now, I want to design a controller that will make the closed loop system have an overshoot ...
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1answer
33 views

Implementing logic expression and the truth table of logic function

(a)Z=(B+C')A+B(C+D')+BD Z=AB+AC'+BC+BD'+BD Z=AB+A'C+B Z=B+AC' (b) A B C|Z 0 0 0|0 0 0 1|0 0 1 0|1 0 1 1|1 1 0 0|1 1 0 1|0 1 1 0|1 1 1 1|1 (c) BC 00 01 ...
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2answers
66 views

If gold is a worse electrical conductor than silver and copper, why are gold plated contacts considered “better” by the market?

I've always wondered if this is just a marketing thing, but all across the electronic supply spectrum I see "gold plated" listed as the best conductors for various contacts and connectors. However, ...
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2answers
60 views

Can you use an electromagnet to break the connection of a permanent magnet?

At first, I had a particular goal, but I'm starting to doubt feasibility which has led me here. Original Goal: Create a small (3in²) electromagnet with 100% duty cycle capable of holding at least ...
13
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1answer
118 views

What is it about the cabin electrical supply on cruise ships that makes surge protectors dangerous?

Surge protectors are banned on cruise ships, and so are confiscated during boarding. Extension cords and cube taps etc. are discouraged, but not banned. I'm asking specifically about surge protector ...
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1answer
17 views

Measuring wire damage using strain gauges

We need to determine the physical damage in some area of overhead lines that can't be inspected visually. The damage's in general caused by short circuit and air pollution (mostly sulphur compound). ...
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1answer
26 views

Can a switched mode power supply for a neon sign be used for making lichtenberg figures?

I am trying to find a cheap power supply that will produce the high voltage needed to create lichtenberg figures on wood. I ruled against using a microwave oven transformer due to the high current, ...
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1answer
19 views

Difference between AD630 'Phase Comparator' and 'Lock-in Amplifier' modes

The datasheet of the AD630 mentions that the device can be used as a Precision Phase Comparator or as a Lock-in Amplifier. What's the difference? They both seem to map the amplitude of a modulated ...
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0answers
24 views

Power generation in combustion engine

Here's the problem: On the one end of low-speed engine (driving end) I can measure the torque transformed to mechanical energy. On the other end (free end) I'd like to join power generator with a ...
1
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1answer
54 views

Strange simulink error. Professor & TA don't know. Any Ideas?

I am currently working on developing a simulation for a restricted UAV, and I’m having some issues with Simulink while doing this. I have my mathematical equations which have been approved by my ...
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0answers
15 views

Why are Microbolometers uncooled?

i've read on several websites that microbolometer, unlike other low range infrared waves detector, does not requiere any cooling. I didn't find any explaination online. For me, the core principle of ...
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0answers
28 views

Name of protocol used to communicate with Fuelling Station Dispensors

I am trying to figure out the actual (Range of ) communication protocols used to communicate with Fuel Dispensers at fuel retail outlets. I see them write 2-wire protocol which is not specific as ...
1
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1answer
106 views

Basetech BT-305 missing resistor

I just modded my Basetech BT-305 laboratory power supply to become an IoT device. Everything works as planned, except the volt display in the multimeter-part of the supply, which is directly shown ...
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0answers
21 views

Can a Tesla Powerwall 2 be rate limited?

Can a telsa powerwall 2 be rate limited (discharge/charge)? I have access to realtime electricity rates (30 min update interval) and also access to 12 hour predicted look ahead. So I wish to limit ...
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2answers
89 views

Find the system response given the initial condition

I am given these sets of equations for a gantry crane: 1) $M\frac{d^2x}{dt^2}+D\frac{dx}{dt}-mg\theta =u$ 2) $ml\frac{d^2\theta }{dt^2}+mg\theta +m\frac{d^2x\:}{dt^2}=0$ 3) $y=x+l\theta $ Where $x$...
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0answers
39 views

Need help picking motor to wind a spool

The application is a motor attached to a spool to wind/unwind window blinds. I would like to operate the motor at $v=0.2\text{ m/s}$, with a max load of 1.5 kg. I need to know the ideal diameter ...
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1answer
45 views

Hot neutral in UPS devices in battery mode

I have faced a problem with ITYS E-3KVA UPS device. While operating in the in-line mode the measured neutral-ground voltage is almost equal to zero. However, during the battery mode the neutral-ground ...
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0answers
40 views

Determining thrust equations for a custom UAV

I have been tasked to mathematically model and simulate a 2 propeller, 2 motor UAV. But I am struggling with determining the thrust equations, of the propeller, for my design. I know that: Ft = Ct * ...
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4answers
69 views

Why hydroelectricity needs to flood so much land surface if only the height difference matters (hydrostatic pressure is not affected)?

Taking into account the fact that what matters in hydroelectric power generation is the potential energy of water, one would be led to the conclusion that we do not need the rest of the reservoir on ...
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1answer
15 views

What is the mechanism of transition in applications of finite state automata?

Just began studying automata. I've already seen several examples of the applications of finite automata: pattern matching, automatic doors, etc. And so far, I understand the logical connection between ...
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0answers
34 views

12v relay to open and an close switch without sending power to switch

Sorry if this is elementary but here's what I need. I'm trying to power a relay via 12v DC (vehicle) to open a closed switch while the 12v power is sent to the relay. Essentially, when the blinkers ...
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1answer
38 views

How to choose type of output from a water level switch?

I need to buy a level switch for a quench tower water drainage system. I intend to use its output directly to open a solenoid valve to drain the tank when the switch detects water and close it ...
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1answer
40 views

Can magnetic stripes be read wirelessly with lasers or other technologies?

I know that magnetic stripes used in credit cards and audio tapes are typically read by a magnetic reader head. But is it theoretically possible for the stripe to be read by a laser in a similar ...
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0answers
24 views

What motors to use to guide tape with high speed

My field isn't dealing with motors and such at all, however, I now need to build something that controls two motors. So I have two guiding reels with tape between them, similar to old tape recorders. ...
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1answer
24 views

Sonomotors, Sion: Can this electric car really charge up to 30km only from its solar cells?

Maybe you have heard about Sonomotors and its futuristic electric car, the Sion. If not, here is the link to its website: https://sonomotors.com/ Anyway, the manufacturer claims that this car can ...
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0answers
20 views

Communications Question: Resource block parameters?

I am modelling a network using MILP/AMPL; in this network there are a multitude of UEs and 16 basestations (BS) (4 macro cells, 12 small cells). Each BS has resource blocks (RB) consisting of 12 ...
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0answers
22 views

PWM to analog RC based filter with minimum analog voltage level

Trying to design a circuit to accomplish the following: 5V PWM signal is converted to 0-2.5V analog voltage The analog voltage should never drop below a certain minimum voltage level, when PWM is 0 ...
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0answers
21 views

Example induction motor

I have three phase induction motor: $U=6\text{ kV}$ $P=630\text{ kW}$ $f_1=50\text{ Hz}$ speed of rotor $n=1410\text{ rpm}$ Maximum moment is reached when $n=1120\text{ rpm}$. Now voltage and ...
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1answer
30 views

Voltage controlled switch?

So I am in the process of working on a rather strange and specific project. I am looking to capture as much energy as possible from a small steam turbine using a DC motor and then use that to power ...
1
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1answer
44 views

Choosing a proper BLDC motor for lab centrifuge

I'm trying to make a swing rotor centrifuge and find a proper BLDC motor to reach 6000G with capacity of 4x50ml Falcon tubes. I did the calculations roughly but I'm not so sure about them and also ...
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1answer
33 views

Build Device for Emitting Weak Air Bursts at Specified Frequency

I'm a neuroscientist interested in building a device to replicate the following study. https://www.nature.com/articles/s41598-018-24924-9 Essentially, they sent air through a nose catheter to ...
0
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1answer
24 views

Unbalance voltage mesurements from 63 kV power transformer

After testing a power transformer(pt) and closing its wiring terminals I've encountered that phase S 63 kV correct voltage and phases R and T shows incorrect voltage 32 kV. Can any body tell why?
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0answers
29 views

How to prototype this circuit using an Arduino and breadboard?

I'm trying to build this circuit for a force transducer such that the data is logged by an Arduino Uno. I have the op-amp recommended in the schematic, but I haven't been able to get stable readings ...
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0answers
25 views

detection and verification

we are building a smart cat door that will unlock automatically when ONLY our cat is close to it (within a range of 3 ft). we tried using RFID, however it has a limited range, which was less than 2 ...
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0answers
17 views

Help on solving and deriving equations for the Output Voltage on a Voltage Divider with a Load Resistance?

I'm having trouble understanding how to derive the equation to solve the output voltage for a voltage divider with a load resistance. One of the problems that I'm solving says that the equation is Vo ...
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1answer
62 views

What is the capacity of a WWII Submarine battery in kWh?

After reading about submarines in World War II, I was curious about their battery capacity, specifically in comparison to modern Battery Electric Vehicles (ie Tesla, Bolt, Leaf, i3, etc). I haven't ...
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0answers
14 views

Does the frequency of input voltage in induction motors have to be continuously altered?

I understand that for magnetic lines of the rotating magnetic field to cut the windings of the rotor (and induce current), the field has to rotate at a slightly higher rate than the rotor. But if we ...
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2answers
38 views

Why does aluminum clad steel wire have high corrosion resistance?

Why do aluminum clad steel wires have high corrosion resistance despite being two dissimilar metals? Does the aluminum act as a protective & sacrificial layer similar to zinc in galvanization or ...
1
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1answer
27 views

Satellite Thruters with reversers

Are there any satellite thrusters that mimic the "thrust reversal" feature of airplanes i.e. (A320...). I already know of procedures to decelerate a satellite such as using two separate thrusters ...
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0answers
13 views

How to identify trip coil circuits of Circuit Breaker?

Recently I've encountered Cercuit Breaker without any control circuit diagram. Just many teminals and wires without any tag! I want to do timing test of CB. How can I identify trip coil circuit?(Using ...
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0answers
9 views

Individually Addressable Motor Strip

Can you make an individually addressable motor strip if you replace led with motors?
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2answers
61 views

Activating lights using a motion sensor?

I was wondering how I would configure some sort of setup to get lights like this turn on a timer once activated by a motion sensor. I want them to turn on for about 15 seconds and then turn off once ...
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1answer
26 views

How much power will 4 germicidal lamps use?

I was wondering if this portable power supply will be sufficient for running 4 UVC lamps all at once. If so, for approximately how long? Power Supply: SUAOKI G100 27000mAh /3.7V Power Bank Station ...
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1answer
24 views

Camera and light frequency rate

I recently became curious why some lights flicker in some videos, and I read some explanation about it, and I still have some questions. 1. Does every light have to have a frequency? can it have an ...
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1answer
54 views

Why are phones not getting charged when I supply 5 V and 0.3 A?

I'm using thermoelectric module to get the voltage. With the help of it, I'm getting 3 volts Open circuit voltage. I've attached DC-DC converter which regulates this voltage to 5 volts. I've attached ...
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1answer
39 views

A board or mat that we can detect a push at an exact point

Is there any kind of board or mat that when we place it on the floor and wire it, a self-made connected device can read these data when it is being pushed and holding onto it, at multiple points? ...