I had some time on my hands today as the parts I was waiting for still >haven't turned up. I hooked up my HT PSU which is continuously
variable between zero and 400VDC and decided it would pass some time
to blow up some old caps. I took a 1uF 10V electro and applied just
over 100V across it. Just for good measure, I wired it up with the
polarity reversed. ***BANG!!!*** Jeezus they don't half go! My ears
are still ringing. I did put on safety glasses but that was all. I
think if I'd been hit by any little bit of that thing it would
probably have drawn blood. At this point I decided it would not be
wise to move on to blowing up any larger caps. I'm still curious to
know how big a bang one would get from hooking up say a 10,000uF cap
to the mains, though. Anyone tried this?
I had some time on my hands today as the parts I was waiting for still haven't turned up. I hooked up my HT PSU which is continuously
variable between zero and 400VDC and decided it would pass some time
to blow up some old caps. I took a 1uF 10V electro and applied just
over 100V across it. Just for good measure, I wired it up with the
polarity reversed. ***BANG!!!*** Jeezus they don't half go! My ears
are still ringing. I did put on safety glasses but that was all. I
think if I'd been hit by any little bit of that thing it would
probably have drawn blood. At this point I decided it would not be
wise to move on to blowing up any larger caps. I'm still curious to
know how big a bang one would get from hooking up say a 10,000uF cap
to the mains, though. Anyone tried this?
I had some time on my hands today as the parts I was waiting for still haven't turned up. I hooked up my HT PSU which is continuously
variable between zero and 400VDC and decided it would pass some time
to blow up some old caps. I took a 1uF 10V electro and applied just
over 100V across it. Just for good measure, I wired it up with the
polarity reversed. ***BANG!!!*** Jeezus they don't half go! My ears
are still ringing. I did put on safety glasses but that was all. I
think if I'd been hit by any little bit of that thing it would
probably have drawn blood. At this point I decided it would not be
wise to move on to blowing up any larger caps. I'm still curious to
know how big a bang one would get from hooking up say a 10,000uF cap
to the mains, though. Anyone tried this?
On Sun, 31 Dec 2023 18:24:08 +0000, Cursitor Doom <cd@notformail.com>
wrote:
I had some time on my hands today as the parts I was waiting for still >>haven't turned up. I hooked up my HT PSU which is continuously
variable between zero and 400VDC and decided it would pass some time
to blow up some old caps. I took a 1uF 10V electro and applied just
over 100V across it. Just for good measure, I wired it up with the
polarity reversed. ***BANG!!!*** Jeezus they don't half go! My ears
are still ringing. I did put on safety glasses but that was all. I
think if I'd been hit by any little bit of that thing it would
probably have drawn blood. At this point I decided it would not be
wise to move on to blowing up any larger caps. I'm still curious to
know how big a bang one would get from hooking up say a 10,000uF cap
to the mains, though. Anyone tried this?
You'll get a bigger bang if with more voltage and less capacitance.
U = 0.5 * C * V^2
Double the voltage gives you 4 times the stored energy.
Yes, I've had some experience making big bangs with high voltage
capacitors. No, I don't want to discuss it. Well, maybe a few hints.
What you experienced with the electrolytic capacitor was a steam
explosion where the heat generated by pushing current through the
internal resistance of the capacitor produced enough heat to boil the >electrolyte. The sealed casing or can provided the necessary
confinement. As you get into physically larger capacitors with oil >dielectrics, it will be the oil that is headed and explodes.
Please remember that you have only one life to give for your hobby.
On Sun, 31 Dec 2023 11:01:34 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:
On Sun, 31 Dec 2023 18:24:08 +0000, Cursitor Doom <cd@notformail.com> >>wrote:
I had some time on my hands today as the parts I was waiting for still >>>haven't turned up. I hooked up my HT PSU which is continuously
variable between zero and 400VDC and decided it would pass some time
to blow up some old caps. I took a 1uF 10V electro and applied just
over 100V across it. Just for good measure, I wired it up with the >>>polarity reversed. ***BANG!!!*** Jeezus they don't half go! My ears
are still ringing. I did put on safety glasses but that was all. I
think if I'd been hit by any little bit of that thing it would
probably have drawn blood. At this point I decided it would not be
wise to move on to blowing up any larger caps. I'm still curious to
know how big a bang one would get from hooking up say a 10,000uF cap
to the mains, though. Anyone tried this?
You'll get a bigger bang if with more voltage and less capacitance.
U = 0.5 * C * V^2
Double the voltage gives you 4 times the stored energy.
Yes, I've had some experience making big bangs with high voltage >>capacitors. No, I don't want to discuss it. Well, maybe a few hints.
What you experienced with the electrolytic capacitor was a steam
explosion where the heat generated by pushing current through the
internal resistance of the capacitor produced enough heat to boil the >>electrolyte. The sealed casing or can provided the necessary
confinement. As you get into physically larger capacitors with oil >>dielectrics, it will be the oil that is headed and explodes.
Please remember that you have only one life to give for your hobby.
Thanks for that, Jeff. Yes, one was enough for today! It just struck
me that there might be some scope to use this 'phenomenon' as a
propellant to blast some cylindrical projectile out of a barrel and
measure the energy released (comparative measurement, anyway) by the
depth said projectile was able to penetrate a block of wood. There
ought to be some formula to convert those factors (projectile weight,
cross sectional area, depth of penetration etc) into a credible figure
in joules. That way you could more readily compare the energy released
by igniting different caps with different voltages and seeing what - >literally - gives you the most bang for your buck! Sadly I don't think
I'll ever have the time, though as there are too many other pressing
tasks I need to get to grips with. So no time for any more fun, sadly.
:(
I had some time on my hands today as the parts I was waiting for still haven't turned up. I hooked up my HT PSU which is continuously
variable between zero and 400VDC and decided it would pass some time
to blow up some old caps. I took a 1uF 10V electro and applied just
over 100V across it. Just for good measure, I wired it up with the
polarity reversed. ***BANG!!!*** Jeezus they don't half go! My ears
are still ringing.
I had some time on my hands today as the parts I was waiting for still haven't turned up. I hooked up my HT PSU which is continuously
variable between zero and 400VDC and decided it would pass some time
to blow up some old caps. I took a 1uF 10V electro and applied just
over 100V across it. Just for good measure, I wired it up with the
polarity reversed. ***BANG!!!*** Jeezus they don't half go! My ears
are still ringing. I did put on safety glasses but that was all. I
think if I'd been hit by any little bit of that thing it would
probably have drawn blood. At this point I decided it would not be
wise to move on to blowing up any larger caps. I'm still curious to
know how big a bang one would get from hooking up say a 10,000uF cap
to the mains, though. Anyone tried this?
It just struck me
that there might be some scope to use this 'phenomenon' as a
propellant to blast some cylindrical projectile out of a barrel and
measure the energy released (comparative measurement, anyway) by the
depth said projectile was able to penetrate a block of wood.
There
ought to be some formula to convert those factors (projectile weight,
cross sectional area, depth of penetration etc) into a credible figure
in joules.
That way you could more readily compare the energy released
by igniting different caps with different voltages and seeing what - >literally - gives you the most bang for your buck!
Sadly I don't think
I'll ever have the time, though as there are too many other pressing
tasks I need to get to grips with. So no time for any more fun, sadly.
:(
On Sun, 31 Dec 2023 18:24:08 +0000, Cursitor Doom <cd@notformail.com>
wrote:
I had some time on my hands today as the parts I was waiting for
still haven't turned up. I hooked up my HT PSU which is continuously >variable between zero and 400VDC and decided it would pass some time
to blow up some old caps. I took a 1uF 10V electro and applied just
over 100V across it. Just for good measure, I wired it up with the
polarity reversed. ***BANG!!!*** Jeezus they don't half go! My ears
are still ringing. I did put on safety glasses but that was all. I
think if I'd been hit by any little bit of that thing it would
probably have drawn blood. At this point I decided it would not be
wise to move on to blowing up any larger caps. I'm still curious to
know how big a bang one would get from hooking up say a 10,000uF cap
to the mains, though. Anyone tried this?
You'll get a bigger bang if with more voltage and less capacitance.
U = 0.5 * C * V^2
Double the voltage gives you 4 times the stored energy.
Yes, I've had some experience making big bangs with high voltage
capacitors. No, I don't want to discuss it. Well, maybe a few hints.
What you experienced with the electrolytic capacitor was a steam
explosion where the heat generated by pushing current through the
internal resistance of the capacitor produced enough heat to boil the electrolyte. The sealed casing or can provided the necessary
confinement. As you get into physically larger capacitors with oil dielectrics, it will be the oil that is headed and explodes.
Please remember that you have only one life to give for your hobby.
On Sun, 31 Dec 2023 19:36:56 +0000, Cursitor Doom <cd@notformail.com>
wrote:
It just struck me
Hopefully, it did not strike you very hard.
that there might be some scope to use this 'phenomenon' as a
propellant to blast some cylindrical projectile out of a barrel and
measure the energy released (comparative measurement, anyway) by the
depth said projectile was able to penetrate a block of wood.
Sure. Just put the capacitor in a suitable gun like device. Stuff a >projectile down the barrel and a capacitor in the chamber. Apply
power and the steam or oil explosion will do the rest. Unfortunately, >capacitors are not designed for efficient combustion so the useful
power might be rather limited. I think the big problem will be the
slow recharge time. Charging energy storage caps to kilovolt levels
can take something close to forever.
Perhaps if you start with a coil gun. (That's a coil gun, not a rail
gun).
<https://www.electroboom.com/?p=101> ><https://www.youtube.com/watch?v=mdZo_keUoEs>
You'll probably like ElectroBoom. He make videos of things that
explode, electrocute, burn etc and posts them to his YouTube channel. ><https://www.youtube.com/@ElectroBOOM/videos>
There
ought to be some formula to convert those factors (projectile weight,
cross sectional area, depth of penetration etc) into a credible figure
in joules.
That's been done for firearms. The result is muzzle energy in ft-lbs.
1 joule = 0.737562 ft-lbs
1 ft-lb = 1.35582 joules
Everything beyond the muzzle is called ballistics. There are tables
for the energy required to penetrate various materials but I'll
pretend not to know anything about those.
That way you could more readily compare the energy released
by igniting different caps with different voltages and seeing what - >>literally - gives you the most bang for your buck!
All you need it the weight of the projectile and its velocity. There
are ballistics tables and calculators that will provide the remaining >velocity at a given range.
Sadly I don't think
I'll ever have the time, though as there are too many other pressing
tasks I need to get to grips with. So no time for any more fun, sadly.
:(
Good. For a moment, I thought you were serious. Please find
something to do which is safer and less destructive.
Please remember that you have only one life to give for your hobby.
On 2023-12-31 19:24, Cursitor Doom wrote:
I had some time on my hands today as the parts I was waiting for still
haven't turned up. I hooked up my HT PSU which is continuously
variable between zero and 400VDC and decided it would pass some time
to blow up some old caps. I took a 1uF 10V electro and applied just
over 100V across it. Just for good measure, I wired it up with the
polarity reversed. ***BANG!!!*** Jeezus they don't half go! My ears
are still ringing. I did put on safety glasses but that was all. I
think if I'd been hit by any little bit of that thing it would
probably have drawn blood. At this point I decided it would not be
wise to move on to blowing up any larger caps. I'm still curious to
know how big a bang one would get from hooking up say a 10,000uF cap
to the mains, though. Anyone tried this?
At one lab on uni, I remember they had electrolytic caps wired beneath the methacrylate boards. All other components were on top, but this one was beneath the board.
When we asked, they pointed to a stain on the ceiling.
And when some of us volunteered to work as aides the next year, they stressed on us to be very vigilant about when the newbies connected the caps.
Another point to watch were a pot, when connecting to get a variable ac voltage to calibrate a meter.
110v ---\
/
\
/<--------
\
/
0C-----\----------
Well, some one connected the 110 (which here is half the mains,
as a precaution) on the right hand. And he had a baffled face
when it went up in smoke as he turned the spindle :-DD
I had some time on my hands today as the parts I was waiting for still >haven't turned up. I hooked up my HT PSU which is continuously
variable between zero and 400VDC and decided it would pass some time
to blow up some old caps. I took a 1uF 10V electro and applied just
over 100V across it. Just for good measure, I wired it up with the
polarity reversed. ***BANG!!!*** Jeezus they don't half go! My ears
are still ringing. I did put on safety glasses but that was all. I
think if I'd been hit by any little bit of that thing it would
probably have drawn blood. At this point I decided it would not be
wise to move on to blowing up any larger caps. I'm still curious to
know how big a bang one would get from hooking up say a 10,000uF cap
to the mains, though. Anyone tried this?
know how big a bang one would get from hooking up say a 10,000uF cap
to the mains, though. Anyone tried this?
On 12/31/2023 2:35 PM, Carlos E.R. wrote:
On 2023-12-31 19:24, Cursitor Doom wrote:
Another point to watch were a pot, when connecting to get a variable ac voltage to calibrate a meter.
110v ---\
/
\
/<--------
\
/
0C-----\----------
Well, some one connected the 110 (which here is half the mains,
as a precaution) on the right hand. And he had a baffled face
when it went up in smoke as he turned the spindle :-DD
[Picture]
https://i.postimg.cc/rFKXgJ1f/Mister-Potentiometer.gif
And the reason this happens, is the treatment of potentiometers is poor in Introductory Electronics.
The students end up in the Power Lab, with no practical experience
or education about pots.
Basically, the students are given a three terminal device, without
knowing the canonical (practitioner) usage forms. And they're sent
into Power Lab, to learn about the behavior "at scale" :-) The
best way to learn. Nothing reinforces a mistake better, than
a cloud of smoke. Right ?
In my Power Lab, one of the student teams, just put the ends of
the rheostat across mains (240V). I calculated later, that this mis-step dissipated about 5kW. No reason for the breaker to open of course.
And it made a festive Yule Log out of the device,
glowing bright cherry red like an "electric fire". The device got hot
enough, the coils of wire fell of it. Such a beautiful piece of handiwork. Stu-dentin.
On 22:32 31 Dec 2023, Brian Gregory said:
On 31/12/2023 19:01, Jeff Liebermann wrote:
Please remember that you have only one life to give for your hobby.
And that capacitors may contain unpleasant, and possibly even mildly
poisonous chemicals. You can end up with a mess that it takes more than
just a dustpan and brush to clean up.
As a child, I got rid of some dead zinc-carbon batteries by throwing them onto the coal fire in the living room. What a noise and what a mess.
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