Questions tagged [electrical]

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21 views

Removal of bonded kettle element from kettle base using chemical methods

I have asked the below question via electronic SE site, which is off topic, so tried to ask here, the question text is: --------------- I have one tea maker ...
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1answer
23 views

Is it possible to build a DIY RLC circuit for a classroom demonstration?

I was describing the mathematics of RLC circuits to my students, and was wondering if it's possible to build an actual RLC circuit with coils of wire and an inductor and a variable capacitor. The ...
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32 views

Why does adapter with higher ratings put out less heat?

Just wondering if anyone can explain why this might be happening... I have two adapters with wires stripped and rigged up to make a hot wire foam cutter. The first (usb) adapter is 5V 1.2 amps. ...
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2answers
49 views

How is electrical building code defined and applied to new constructions?

A new home (completed in early 2020) in San Jose California does not have GFCI outlets in all the bathrooms. I thought this was a requirement (according to https://www.redwoodcity.org/home/...
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2answers
47 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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0answers
13 views

DIY device to repeatedly depress and release gas pedal on a vehicle

The pedal needs to be depressed about 1/2 to 1 inch, once every three minutes. I believe the best way to do this will be with a rotating arm of length 2 to 2 1/2 inches that has rollers on each end, ...
2
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1answer
82 views

Can I connect a power supply main (SPH) and inverter main (SPH) with common neutral to a TP MCB?

I have limited knowledge of MCBs and just doing research to secure my kitchen. I want to connect my power supply main and inverter main with common neutral to a TP MCB. This MCB will be placed in the ...
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32 views

What is the fastest possible slot car

What is the fastest possible slot car one can build? What are the limiting factors? Obviously, we have to require that the motor is aboard the car and that it's propelled by the wheels (we don't want ...
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3answers
69 views

Why does audio equipment buzz/humm when a long signal cable is used and how do I eliminate it?

I have two 5.1 speaker sets, one in the front and one in the back of my living room. I have connected them together with an "audio wire" (non-shielded unfortunately) that's 12 meters in length. Since ...
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0answers
34 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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2answers
73 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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1answer
35 views

What is the best practice for ensuring the best possible connection between a battery cable and a battery terminal

I've seen a number of opinions on conductive gels to ensure the best conductivity between battery terminals and battery cables. I'm interested in knowing an expert's opinion on the matter. I'm ...
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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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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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0answers
18 views

solving short electricity interruptions with an UPS

Context A plastics factory with installed power of about 500 kVA. Most of the consumption is represented by motors and resistances. Problem There are several (8+ a day) power interruptions, lasting ...
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1answer
22 views

Static electricity in PE foam rolling

In a PE (polyethylene) foam factory there have been some incidents with static electricity that have created minor fires. Fire is a concern in such a factory, as PE is highly flammable, and even more ...
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1answer
45 views

Do kids under a certain age not hear the warning beeps that smoke detectors make when they are running out of battery power?

I've always been very annoyed by those regular single beeps that smoke detectors start doing increasingly often as the batteries start to run out, to warn the user to replace the batteries. Lately, I'...
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3answers
37 views

what to learn to design mechatronics device that move [closed]

I want to design an artificial leg for disabled people. The idea is design of a Device for patients with problems on one side of the leg from the knee down. This device first detects intent to move ...
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0answers
28 views

How can I find the length of 12 gauge wire needed for a cone of if I know it's surface area

So I'm working on a personal project, and I need to figure out how much 12 gauge wire (which is ~2mm thick) I would need to cover a cone shaped rubber core, which has a surface area of roughly 3,417,...
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1answer
36 views

What's the function of those coils there?

What do they do? The aux contacts are normally open and the device is MR PQM 500 reactive power compensation system.
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1answer
100 views

AC Motor On/OFF Control using SSR instead of contactor

I would like to control a 1-phase 3HP motor using a SSR ( the reason being, I need to switch it on/off using a signal (0-5VDC). Are normal SSRs (ex:Fotek 40A model) capable of handling the starting ...
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1answer
29 views

Low voltage power transmission

i want to transmit 9v dc power overhead in 500 meter range. please tell me most suitable method for it. i didn't tried it but i am making this system for operating 9 Volt router of wifi device.
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2answers
37 views

Voltage at node A respective to the ground

I want to calculate the voltage at node $A$ respective to the ground. $R_1=1.8\text{k}\Omega, R_2=3.8\text{k}\Omega, R_3=1.8\text{k}\Omega, R_4=5.8\text{k}\Omega, R_5=2.4\text{k}\Omega$ and $V1=4.3V, ...
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1answer
54 views

Circuit analysis, voltage in and voltage out

I want to solve $V_o$ in terms of $V_i$ from the following circuit. $R_1=95.7 \Omega, R_2=9.1 k\Omega, R_3=1.0 M\Omega$ So the solution is form $V_o=kV_i$ and I want the factor k. I know that:...
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1answer
43 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
13 views

Electric Current Based Shape-Memory Alloy

Would it be possible to create a piece of metal, made out of an alloy or combination of alloys, that undergoes a shape-memory-esque change in structure in reaction to an electric current? Could it ...
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2answers
46 views

DC Motor Question

I am not an engineer, just looking for a bit of advice. I hope that it is ok that I ask this here. I have a DC Motor from a treadmill. It is a DC 2.25hp, 180v, 4700 RPM, 7.5 amp motor. I want to use ...
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1answer
48 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
88 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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2answers
125 views

PC Controllable DC Power supply (0-30V)

I have a Proportional solenoid valve that uses a 0-30VDC for control (opening the orifice) I only have capability to provide 0-5V or 0-10V. I need to control the valve using my PC. Is there any DC ...
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2answers
55 views

Electric bicycle and an electric scooter

Assuming that an electric bicycle and an electric scooter use the same motor and battery, which has more autonomy? that is, which makes more kilometers / miles per battery charge cycle? Obviously each ...
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0answers
28 views

Generally speaking are inrunner motors better generators than outrunner motors or vice versa?

Using a motor as a generator but looking to test something I understand that outrunners have a higher torque but would that be neccesarily good for generating electricity or not?
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0answers
56 views

best refractory cement for embedded heating element furnace

first post I designed a 2000 watts 1000 degrees Celsius furnace with following chamber size: 11 cm length, 12 cm width and 15 cm depth. The refractory that I use is 1880 C high temp tabular alumina ...
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1answer
44 views

How effective are pancake motors as generators and why

Using a motor as a generator but looking to test something Why would or would they not be good generators thanks
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1answer
42 views

LPF Second Order use cascade

What is the minimum value of $R_2$ (in $R_1$) to minimize loading effect? Please explain the concept.
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2answers
42 views

Integrator OpAmp

Tell me how can the 's' in first equation described with the 'integration' in second equation?
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1answer
50 views

Operational Amplifier

In this case, can I say that $V_E$ correspond to -0.7? if yes, why can this be?
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0answers
45 views

Finding Supply/Nominal voltage for Torque Motor BLDC

I'm a bit confused by torque motors datasheets as it never mentions any nominal voltage. I would like to run a torque motor on a 24 V battery. The required max torque is 150 Nm (=21000 ...
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1answer
34 views

What is the material requirement for Van der Graff generator sphere?

I would like to make a Van der Graff generator for my science fair project out of aluminized mylar. Do you think this might be feasable or do I need to use thick stainless steel ball? Is there some ...
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1answer
67 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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0answers
196 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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3answers
56 views

corrosion in electrical parts and wiring

I work in a pharmaceutical plant where saline solution is produced and bottled. The environment has to be clean (by pharma standards), which rules out many greases and other protective coatings. As ...
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1answer
35 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 ...
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0answers
37 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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2answers
70 views

What is the name and purpose of this Instrumentation / Mechanical fitting

The component I am interested in is the blue "head" in the attached image. I call it the sensor head but will like to know if it has a specific industry name
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1answer
111 views

Electric Motor Sizing : Understanding how much torque I need given Force

Physics has never been my strong point... I have a task to size a motor. The question is: Based on information below, how do I calculate required motor torque to accelerate a mass with the ...
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1answer
66 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
122 views

How do renewable energy sources deal with reactive loads?

If a power grid were to fully switch to renewable power generation methods how would they deal with reactive loads?
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1answer
30 views

Breath Sensor: A low range pressure sensor that won't be affected by humidity

I am designing a device that will measure the force of a breath through a tube. A small differential pressure sensor like this https://www.digikey.ca/product-detail/en/MPX10DP/MPX10DP-ND/464046 would ...
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0answers
109 views

LED Lights Dimmer Electronics

I have a Wemo Smart WiFi Smart Dimmer with me that can control CFL, Incandescent and LED lights. (https://www.belkin.com/us/p/P-F7C059/). I am curious to know how one device can handle all type of ...