35
votes
Accepted
Is it really possible to "boost" 6 V DC to above 50 kV? Or even 400 kV?
Is it really possible to “boost” 6 V DC to above 50kV? Or even 400kV?
Of course. One common example of something similar (although not as extreme as your specs) is using 12 V in a car to make ...
- 314k
32
votes
Accepted
Why does only the tip of the electrode melt when arc welding?
The electrode's resistance isn't what's heating things up – it's the resistance of the ionized air in the arc!
Hence, things close to the arc get hot, and things farther away don't.
- 98.2k
32
votes
Accepted
Why do fuses have a maximum breaking capacity?
To elaborate a bit on the answer by Neil_UK...
At a modest overload, the fuse wire will melt at its weakest point, and break the current.
At a larger overload, an arc will form across the ends of ...
- 19.6k
30
votes
Accepted
How can low voltage, high current (kA) power be dangerous?
The voltage for the Hall–Héroult process is inconveniently low (and the current too high) for efficient parallel operation so they use a whole bunch of cells in series.
From this source ("Studies on ...
28
votes
Accepted
Stopping electric arcs between layers in PCB - big PCB burn
A DC arc can't be reasoned with
It can't be bargained with. It doesn't feel pity, or remorse, or fear. And it absolutely will not stop, ever, until it burns up so much material that it can no longer ...
26
votes
Why might a low-cost soldering iron die after short use?
Just looking at how these wires are soldered to the PCB indicates a low quality product. I would not blame you but the product instead.
- 1,552
25
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Why do fuses have a maximum breaking capacity?
I don’t understand that if a small current can blow the fuse, why a bigger current can’t.
A bigger current will indeed melt the fuse wire. The question is, what happens after that?
If the fuse is ...
- 171k
24
votes
How can low voltage, high current (kA) power be dangerous?
The loop of conductor that carries the 10 kA current has non-zero inductance. That means a large amount of energy is stored in that loop as \$\frac{1}{2}LI^2\$.
If there's a break in the circuit, the ...
- 171k
23
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Is it really possible to "boost" 6 V DC to above 50 kV? Or even 400 kV?
A battery powering a dc motor in a Van der Graaff generator can produce a million volts quite easily: -
- 466k
14
votes
Accepted
Why are arcs so hazardous compared to standard current flow?
Arcs generate heat, but shouldn't normal current flow also generate
heat?
The whole point about normal current flow is that it is through a medium called a conductor i.e. a copper wire and, the ...
- 466k
14
votes
Stopping electric arcs between layers in PCB - big PCB burn
Extinguishing a DC arc is quite difficult, primarily because the ionized material resulting from the initial arc has a lower impedence than the intact pre-arc circuit, and the arc is therefore self-...
- 1,258
14
votes
Accepted
Why do electric arcs rise?
When the potential between the two conductors reaches sufficient voltage, it causes a breakdown in the air - ionising the air into a hot plasma between the two conductors. It is this plasma through ...
- 68.6k
13
votes
Is it really possible to "boost" 6 V DC to above 50 kV? Or even 400 kV?
Take your 6 volts and run it through DC-DC boost converter and then an inverter, you now have really rubbish AC at a slightly more respectable voltage.
Feed rubbish AC in to a solid state boost ...
- 250
13
votes
Light bulb burns out -- why there is an arc in the switch?
When the lamps fails, it is often the case that the delicate filament collapes on itself, causing a short circuit. This causes a momentary peak of current. So much current that the short almost ...
- 2,651
12
votes
How far can mains voltage arc in air?
The breakdown voltage of air varies significantly due to changes in humidity, pressure, and temperature. However, a rough guide is that it takes 1 kV per millimeter.
Since that's about where arcs ...
- 314k
11
votes
Is it really possible to "boost" 6 V DC to above 50 kV? Or even 400 kV?
Yes, quite easily. The 1990s had hand-held TVs that actually had Cathode-Ray Tubes like "proper" living room TVs; those were powered using a couple AA batteries (ie. 6V or the like).
CRTs need a ...
- 98.2k
9
votes
Why are arcs so hazardous compared to standard current flow?
Arcs generate heat, but shouldn't normal current flow also generate
heat?
Arcs are the breakdown of air with the resistance going from GigaOhms to less than Ohms in milliseconds of time. This means a ...
- 87.1k
8
votes
How can fumes make this electrical arc travel so far in distance to the other side?
Not smoke, plasma. Plasma arcs have low resistance and are very hot, which causes them to rise. At some point the arc gets too long and cannot be sustained and it disappears or "quenches".
- 21.3k
7
votes
Why are arcs so hazardous compared to standard current flow?
I know that electric arcs are dangerous [etc] However, I am a bit confused why.
An arc creates the fourth state of matter: a plasma. Plasma in air is very hot; it can be over 2500°C in fact. For ...
- 16.3k
7
votes
Accepted
The mosquito zapper from hell: why does it arc at different places instead of at the shortest gap?
What I do not understand is the arcing pattern.... but why isn't the arcing happening at the place where the two parts of the frame would be the closest to each other?
It boils down to Paschen's law -...
- 466k
7
votes
Accepted
Arc welding: Why is electric arc preferred over fire for welding?
Arc and glow discharges can generate virtually unlimited power density. Cosider lightning or magnetic confinement fusion reactor heating. Chemical burning has limited reaction temperatures, spreads ...
- 22.7k
6
votes
What's causing bubbles in my transformer oil?
The bubbles are due to oil decomposing. Transformers have a safety switch that detects this gas and then switches the transformer off line. https://en.wikipedia.org/wiki/Buchholz_relay
- 24.2k
6
votes
How can low voltage, high current (kA) power be dangerous?
A more everyday example of a hazardous low-voltage, high-current source is a humble car battery. Why? Even though the voltage (12V give or take) isn't enough to electrocute or even significantly shock ...
- 9,008
6
votes
Light bulb burns out -- why there is an arc in the switch?
There are several things that cause an arc in the switch.
One of them is worn out contacts. This can be seen on repeatedly/frequently used switches.
Another one is excessive load. Incandescent ...
- 38k
5
votes
Why do cables not arc/spark when being removed or reconnected on a car battery terminal?
You get the same spark if you disconnect the ground cable first. The amount of sparking or arcing depends on the amount of current flowing in the circuit.
You disconnect the ground cable first and ...
- 10.1k
5
votes
Is it really possible to "boost" 6 V DC to above 50 kV? Or even 400 kV?
I'd recommend that you buy Prutchis' book: "Exploring Quantum Physics through Hands-on Projects" and then go to their web links:
d.i.y. 250 kV High Voltage DC Power Supply with Neat Trick for ...
- 78.4k
5
votes
How do I make a “directed” spark gap?
The simplest way to get what you described is a set up like this sketch:
Distance "a" is longer than your arc can jump.
Distance "b" and "c" together are shorter than &...
- 73k
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