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

From USCG Surge Protective Devices Onboard Vessels A marine casualty investigation of two separate stateroom fires onboard a U.S. Flag Container ship revealed that the sources of the fires were ...
StainlessSteelRat's user avatar
9 votes
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What device is this, and how does it work?

Something like this? http://www.browninnovations.com/sound-dome/single-localizer-sound-dome As others have said, it is a speaker with a parabolic reflector to direct the sound down at the listener. ...
Andrew's user avatar
  • 766
8 votes

What device is this, and how does it work?

With a description as vague as that, it was probably a parabolic reflector with a speaker at its focus. Pointed straight down, the "beam" of acoustic energy would be reflected from the floor right ...
Dave Tweed's user avatar
  • 6,884
6 votes
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Why do kWh (smart) meters have a maximum operating altitude?

Electronic components are rated for altitude because: Air density affects convective cooling, both forced and natural, meaning the cooling is reduced at altitude. Air density affects air's dielectric ...
Tiger Guy's user avatar
  • 6,901
4 votes

How can I find the emission power of a WiFi mobile phone antenna?

Typically, the max is 100mW (20dBm). You can refer to an example wifi chip datasheet (This one is used in many mobile phones with Snapdragon processor) - https://developer.qualcomm.com/download/sd410/...
Bharath Patil's user avatar
4 votes
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Why is it bad to run power through BNC (RG58) cables?

Because it is not a power cable (Q1) using power connectors (Q2). BNC cable has a solid conductor and a ground braid to electrically shield and mechanically protect the conductor. Electrical reason: ...
StainlessSteelRat's user avatar
3 votes

How can I find the emission power of a WiFi mobile phone antenna?

There is a list of some widely used devices and their transmit power (and many other properties) in an easily digestible table: https://clients.mikealbano.com/ The most smartphones seem to be just ...
AdamKalisz's user avatar
3 votes

Why are bird flight diverters shaped like a spiral?

Originally the spiral shaped devices were fitted to the earth wires on top of pylons as vibration dampers (the very top single wire on pylons is the earth wire). It was however noted that they also ...
Jon W's user avatar
  • 66
3 votes

Generating practical power without an iron core, but with high RPM

the iron structure(s) inside a generator serve the purpose of minimizing flux leakage, which maximizes the utilization of the magnetic field in generating electricity. One of the ways in which they ...
niels nielsen's user avatar
3 votes

What is the function of jumper pins on a 4 channel relay?

Each channel can be set to be triggered high or low. See User Manual
StainlessSteelRat's user avatar
3 votes

Preventing a DC motor from stalling

Considering that this is a class project, depending on what you use to control the DC motor, you might be able to use current limiting. The technique is called current sensing. When a DC motor is ...
NMech's user avatar
  • 24.3k
3 votes

How to match a circuit relay online

For this specific relay, a quick search returns many results. One of them is from Mouser, an electronics component source. There is a link on the web site for the data sheet for the relay. Some of the ...
fred_dot_u's user avatar
  • 7,122
3 votes
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Why design chargers with USB port on a side rather than top

I think that the power adapter was probably first designed for the North American market. For that market, the design is not flawed.
jsotola's user avatar
  • 355
3 votes

Why do kWh (smart) meters have a maximum operating altitude?

Expanding item 2 in Tiger Guy's good answer I'd say it's definitely about dielectric strength. Electronic devices manufacturing standards (e.g. IEC62368-1) define creepage and clearance distances ...
carloc's user avatar
  • 295
2 votes
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Some questions about liquid nitrogen cooling

Regarding questions 2 and 3, I think you need to look deeper in the chemistry, reactivity, and heat transfer characteristics of Nitrogen. 1) It is not a noble gas. It is reactive, and you benefit ...
Tai Viinikka's user avatar
2 votes
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PED or DSP for mechatronic student

DSP is relevant to any engineering field that involves gathering data and/or controlling something. That includes almost all robotics applications. It's not quite clear just from the title what "...
alephzero's user avatar
  • 12.5k
2 votes

Is current suppose to pass through a capacitors dielectric? What happens if it does?

Here is a good link on Capacitors. Capacitor is a energy storage device. Capacitor can act like a battery. Stored energy is discharged to a device like an LED. Take a look at this capacitor battery ...
DiaperHands's user avatar
2 votes

Control power to a tungsten filament?

We have a test rig that works something like this, to heat up small objects (typically cubes of material with sides a few mm long) to about 1000C fairly quickly. The heat source is a "tube" of ...
alephzero's user avatar
  • 12.5k
2 votes

Power consumption of mining rig?

Since I lack the reputation to write comments: The electricity cost of mining is way higher than the earnings. Small scale mining is not profitable anymore for a long time already, mining farms have ...
OpticalResonator's user avatar
2 votes

why do 15kV 60mA transformers have to be so big?

Voltage and Current multiply to give power. 15kV times 60mA is the same as 60Volt times 15 Amps (=900 Watts) You would not expect that to be a tiny thing, would you? And that power is without ...
bukwyrm's user avatar
  • 186
2 votes
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Maximum amps from a switching voltage regulator

That is an oversimplification. From the data sheet http://www.ti.com/lit/ds/symlink/lm2596.pdf there are two relevant features, internal over-temperature protection and a maximum current limiter (...
alephzero's user avatar
  • 12.5k
2 votes

What is this gigantic high-tech cylinder in the corner of a middle-class Chinese family's living/dining room in Shanghai?

It's a guess, but an informed one, based on the 20°C / 68°F indicator on the digital display. One might believe that this is the desired temperature or the current temperature. From there, it's an ...
fred_dot_u's user avatar
  • 7,122
2 votes

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

This may be for a couple of reasons. The battery voltage will sag during high current draw, if the cutoff is too high it might trip even though the battery has plenty of capacity remaining. It may be ...
Drew's user avatar
  • 1,971
2 votes

Effects of Solar Shield on Electronics Enclosure

If you are worried about the solar radiation (which is understandable), a much more affordable solution might be to put the whole thing in a shade if its possible, with enough clearance from the ...
NMech's user avatar
  • 24.3k
2 votes
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AC Harmonics on a system appearing as DC

In general, a load which is "symmetrical" with regard to the positive and negative half-cycles of the mains will only generate odd harmonics. If the load is not symmetrical and the current ...
Transistor's user avatar
  • 10.8k
2 votes
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Preventing a DC motor from stalling

When you bump the plate on a thread off the edge, the plate tilts, inertia of the motor drives the plate to a larger angle. Deformed plastic grips much stronger than what motor can move. To avoid this ...
Surprised Seagull's user avatar
2 votes
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Power Electronics Project

You will need more than a 220V:12V transformer. Fullwave bridge rectifier output: $$ V_{DC} = 0.637\ V_{MAX} = 0.9\ V_{RMS}$$ This is the generic formula (textbooks), which gives you 10.8V. Higher ...
StainlessSteelRat's user avatar
2 votes

Why doesn't the European Type F plugs use a regular earth pin?

I suspect you are talking about the difference between these two TL;DR: Type F is more usable, while type E has more safety prone features Type F advantages The main benefit of the F type is that it ...
NMech's user avatar
  • 24.3k
2 votes
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Modeling a simple capacitor

Capacitance only depends on its geometry, ... False. Capacitance is also determined by the dielectric (the insulator) between the plates and this can have a huge effect on the value obtained. ... ...
Transistor's user avatar
  • 10.8k

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