Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - T3sl4co1l

Pages: [1] 2 3 ... 7
1
Yes.  Physically what happens is, some part of the die overheats directly or due to drain or gate breakdown, and that fuses everything together.  The slightest failure of this type results in a low resistance between all terminals: effectively, Rds(off) has a ceiling, rather than being an effective open circuit (100M+?), and there is some Rgs for a similar difference.

BJTs can also fail in this way, of course we don't expect the base to have a high resistance at any base voltage, so we might miss its lowered resistance; the collector resistance is however unmistakable.

These are small scale effects.  The resistance seems high to us (kohms), but is actually a dead short just a few micrometers across.  The whole transistor is some mm across, achieving its mohm on-resistance by sheer scale -- millions or billions of cells turning on in parallel.  Shorting out just one, doesn't seem like much from the outside, but it is indeed physical damage on a microscopic scale.

If the resistance is high enough not to disturb the circuit, such a slightly-failed transistor can actually continue to operate and go on unnoticed.  It's not common, but it's interesting that it can happen.

More often, heat in the breakdown region causes it to widen quickly; pretty soon, fault current is drawn from the supply.  In a half-wave switching circuit, effectively the transistor remains on, and pretty quickly fault current is drawn through the switching inductor.  In a full-wave circuit, probably nothing happens at first, but then the opposing transistor turns on, and suddenly it's switching into a short circuit; failure then cascades to both transistors.  In the following milliseconds, the supply capacitors are discharged, vaporizing the already-molten silicon (and bondwires) into plasma; in the following 10s of ms, the mains fuse clears, in which time the transistor's plastic case has already been propelled as hazardous shrapnel.

Using a fast ("semiconductor") fuse, and a minimum of local bypass capacitance, less energy will go into the plasma discharge; perhaps the transistor case merely cracks with a loud report, rather than fragmenting.  Perhaps it doesn't crack at all, and fails with no external evidence.

The final state, whether it's shorted or not, depends on when the fault cleared.  The transistor will eventually serve as a fuse itself, but this only happens much later.  Probably if the case has cracked, the connections are broken as well.  If not, it's probably a three-way short.

When driven by thermal overheating, failure can take 10s to 100s of microseconds of short-circuit conditions (Vds is high while on).  When driven by breakdown, it can be practically instantaneous (e.g. gate oxide failure, most often due to ESD).

Note that, when the device goes three-way short, a large fraction of available drain voltage and current is also available on the gate.  So, expect to replace gate drivers and other related components if this has happened.  Typical TC circuits with drive transformers, may manage to survive this (the transformer saturates in 100s us, shorting out the fault current locally, keeping it away from the driver), but should always be inspected.

This is more than enough time to detect what's going on, so we can design our circuits responsibly to address the one failure mode -- excessive current, faulting, short circuit conditions.  We use what's called a desat detector circuit, and disable drive when excessive current is seen for more than, say, a few microseconds.  This doesn't address voltage breakdown, which must be handled by proper design (drain circuit inductance, gate ESD susceptibility).


For amateur Tesla coils, it seems most likely to me that it's a combination of breakdown and thermal runaway.  Layout really does matter, and yes, even just a few inches of wire matters.  If you've built your circuit poorly, following the schematic but not the layout, the stray inductance will develop excessive peak voltages, and destroy transistors in short order.  It might runs for milliseconds, it might run for seconds, who knows.  It's not an instant failure, transistors are quite robust these days, many of them have an avalanche rating (D-S breakdown, acts like a zener).

Tim

2
Transformer (Iron Core) / Re: wire wound power resistors
« on: May 04, 2020, 08:06:18 AM »
Note that they only achieve their rating when heatsinked, similar to transistors.  They don't have much temp rating (similar plastic filling), and not much overload capacity.  The failure mode is: the plastic melts, decomposes, and pops out like a cork gun, taking some of the element with it.  The element and case may end up open or shorted.

Whereas, the enameled ones are only slightly higher priced (at the usual mainstream distributors, anyway), don't need heatsinks, and can survive glowing red for hours if heavily overloaded.

That said, these are unfairly well rated, for some reason:
https://www.mouser.com/ProductDetail/TE-Connectivity-CGS/THS501K0J?qs=sGAEpiMZZMtbXrIkmrvidHzXe9tGSbePVnWBZTYpuxU%3D
20W without heatsink, 275°C(!) maximum operating.  Also have the best pulse ratings, though only in lower values (under 10 ohms).

But others even within the same family are not so lucky. Look at that THS25 derating curve, yikes!  Always RTFDS!

Compare with:
https://www.mouser.com/ProductDetail/Vishay-Dale/AVT05006E500R0KE?qs=sGAEpiMZZMtbXrIkmrvidAl35n5xACJLdSQS8JyFBDol8cr0PzbUvg%3D%3D
Derated linearly up to 350C ambient; it'll probably handle even more than that, but it may crack, especially if it's overloaded rapidly.  Element tends to fail open, unless, like... some wire bits fall onto nearby mounting hardware, or something.

At high voltages, you might not want to use the end mounting metal clips?  Or you can but mount them in turn on an insulated platform.  Or use ceramic or fiberglass hardware to mount them.  YMMV.

Tim

3
If the winding were reversed, it would be a SEPIC arrangement, backfeeding into the supply to recycle reactive power.  A "quarter bridge" arrangement.  More often(?) seen with a tapped winding as here, left:



If the phasing is in fact correct as shown, it might not be very efficient...

Tim

4
Electronic Circuits / Re: Motor-run capacitor RMS current
« on: April 30, 2020, 05:39:25 AM »
Yes, intended for mains operation, and that's about it.  The connections are typically foil ribbon, giving relatively high ESR and ESL, much lower current capacity than it could be.  The connections may also be fused, by themselves or by gas expansion inside the can forcing the connections apart.  (I have some cylindrical types with an embossed rim that, according to the patent, is supposed to expand like an accordion, pulling the connections apart, under these conditions.)

Tim

5
The transformer also has a lowpass characteristic, limiting rise/fall time in general.  (This can be improved by using a twisted-pair transmission line transformer, with more pairs in parallel to lower the characteristic impedance between the windings; and by using a thicker core, to use less winding wire length.  Thinner wire can also be used, as the RMS current is not very high; though the isolation voltage still is.)

Tim

6
Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Logic question
« on: April 27, 2020, 05:07:42 AM »
That's a duplicate thread, I guess: https://highvoltageforum.net/index.php?topic=1050.0

If you're talking about drivers with transformer outputs, one inversion is obligatory, otherwise nothing comes out.

You can use a single dual complementary driver.  These aren't usually rated as high as single drivers, since, well, there's two of them.
For more output, two separate drivers might be used.
The two can be complementary, in which case you need two part numbers, adding another BOM item.
If they are identical, you need an inverter somewhere.  Which you might already have, for other logic functions.  Otherwise, an inverter must be added, increasing parts count, and maybe adding a BOM item too.

The kind with dual complementary inputs are handy, you can just wire the input for inverting or non-.  I forget if there's a UCC family that has that.  FAN3100 does.  Think some TC4xxx's do?  Lots of families to choose from, in any case.

Drivers with independent gate drivers (usually the dual bootstrap type, or independent isolated driver modules) need the correct polarities and dead timing, else the inverter will be destroyed.

Incidentally, inverters can be made in the current-sourcing type, where dead time is both switches on.  These are less common, but absolutely possible; it's not a foregone conclusion that the inverter is always voltage-sourcing (where dead time is both switches off).  Also, in both cases, a small or even negative dead time can be useful for adjusting commutation efficiency, but this is also not common (or needed) in the present application.

Tim

7
Dual Resonant Solid State Tesla coils (DRSSTC) / Re: Logic question
« on: April 21, 2020, 06:31:39 PM »
Yes, down to timing differences.  Also the dual driver may have dead time generation inside, or may be independent, which also factors into timing.

Tim

8
Transformer (Iron Core) / Re: MOT efficiency improvement idea
« on: April 17, 2020, 09:08:56 PM »
Knock out the shunts (assuming you don't need the current limiting anymore) and wind 20% of the primary turns in that space (carefully, not to nick the wire).  You'll get, well, what you see above, ~20% lower voltage or ~20% more primary turns, same thing.

Fully half is a lot of VAs to sacrifice, but yeah you can do that too.

By "sacrifice", I mean that the available amperes drop proportionally with voltage.  That is, the series impedance (resistance and leakage inductance), what defines the transformer's regulation spec, remains constant, but you're using it for less voltage, so it takes less current to cause the same percent change in load voltage.  This is true even for heavy loads or short circuits (where the full output voltage is dropped across that impedance).  Actually, you'll have even less available under heavy/fault conditions, due to the shunts not saturating under that condition, or as much (assuming they're left in, of course).

To be fair, a typical MOT is only about 500VA worth of material (at continuous duty), but they're wound for almost 1000, so knocking that capacity down by half isn't that bad a deal overall.

Tim

9
Electronic Circuits / Re: TVS diode selection for 400v transistor
« on: April 11, 2020, 10:52:36 PM »
TVSs in series are fine.  Higher voltage devices are stacked dies -- internally in series.

They're alright in parallel too, at least under surge conditions, if maybe not so much at lower currents.

Tim

10
Electronic Circuits / Re: Power MOSFETs with fast recovery body diodes
« on: April 10, 2020, 06:59:00 AM »
But it is a hard switched flyback topology I'm using, but it doesn't matter then?

You gave absolutely no context so I assume the default, a half bridge Tesla Coil or something like that.

Hard switched flyback, forces recovery of the secondary diode.

If you're working with this circuit,
https://highvoltageforum.net/index.php?topic=1007.0
it is also not hard switched, with no diode shown and a snubber provided.

Flybacks are usually driven in quasi-resonant as mentioned above.

Tim

11
Electronic Circuits / Re: Power MOSFETs with fast recovery body diodes
« on: April 09, 2020, 05:10:31 AM »
Again, I_RRM is just what happens during recovery.  Most times you won't be operating in hard switched recovery so this aspect of the waveform will never be seen.

Tim

12
Electronic Circuits / Re: Power MOSFETs with fast recovery body diodes
« on: April 04, 2020, 09:01:32 AM »
Recovery only matters if you're off resonance in the wrong direction (for a typical voltage-sourced inverter: below resonance, giving a capacitive load phase).  Under preferred conditions, load current and channel resistance more than force recovery, and soft switching is maintained.

Max dV/dt is a different parameter, and for that matter, usually hard to exceed without mixing technologies (e.g., you might stress a Si FET with the speed of a SiC or GaN FET).

Avalanche and recovery are indeed in a tradeoff, something to do with minority carriers and their distribution.  Avalanche is best not to rely on in the first place.  Occasional light loading might be fine, but there are few applications where that even comes up, and repetitive full-load avalanche such as a poorly-wired inverter would experience, will quickly lead to destruction.

Tim

13
Electronic Circuits / Re: Pt100 oddities
« on: April 01, 2020, 12:49:21 PM »
I don't get it, Pt100 sensors are usually used for reasonably high precision applications, and the "ultra precision resistors" sound like confirmation.  But then you've got an unstated 4-20mA transmitter, an Arduino (what, 12 bits at best..?), and... floor sweepings from China?

Idunno.  What were you expecting?  What do you actually want?

Within a few percent, after calibration, from random Chinese parts, that could've been plain old carbon film resistors on leads, or something?  Heck, turned out better than I would've expected...

Tim

14
Probably a missing semicolon somewhere then.

Also FYI, declarations are usually placed in headers so they are declared at the top right away; doesn't matter if you're only using it in just one file but it is a more organized style.

Tim

15
Also as the metal heats up, its resistance rises significantly and it can absorb more heat directly.  Getting started is slow but maintaining a heel is easier.

Tim

16
Electronic Circuits / Re: Unusually long-lived electrolytic capacitor
« on: February 26, 2020, 05:51:48 AM »
Capacitors age much more in use than in storage.  As long as it's reformed, it's fine.

Tim

17
Electronic Circuits / Re: Induction heater
« on: February 08, 2020, 03:13:31 PM »
Yes.  Note that the series case expects a constant voltage source, otherwise it's not really ringing up or down it's just doing whatever your current is doing; and the parallel case expects a constant current source, otherwise the same thing.  And to drive each with a square wave, to keep current or voltage within reasonable bounds, you need to use a CV or CC inverter, respectively.

There's also a third case, where the current is sourced from a series inductor, driven by a voltage source inverter.  This has the advantage of parallel resonant operation (the capacitor and work coil can be together) without the burden of a current sourcing inverter, but has the disadvantage of more complicated tuning (for a given work coil, you need to choose tank cap, series inductor and transformer ratio; often transformer ratio is kept fixed, putting more emphasis on the inductor), and an additional work coil that's not doing any work but can indeed consume comparable VARs to the work coil itself.  Some of which resonates with the tank cap, but what's left has to be handled by the inverter.  Therefore the inverter needs excess capacity.

The inverter needs excess capacity anyway, in order to offer any useful tuning range, so that's not really a big distinction.

You can save on capacity if you use a fixed resonance, variable supply inverter (rather than a frequency-shift control), but this does require a variable supply, usually a buck converter stage.  Alternately, you can PWM the inverter itself, but this only works out with a tri-level half bridge (the level must be forced to zero, it can't be allowed to freewheel between pulses), or a phase shift PWM H-bridge.

The Chinese induction boards are parallel resonant, with a sort of current-fed inverter.  The current is sourced from series inductors, but they are not resonant, they are part of the DC supply.  The current can be fairly constant from cycle to cycle, but changes in output voltage are quickly (on the order of several cycles) drawn through the inductors, so that increased output load is reflected as increased (DC) input current.  There's no control here, it's just flat out, whatever power the work coil draws at the given supply voltage.

Tim

18
Yes, indeed the leakage inductance of a toroid, at high frequency, is due to the asymmetry of the fields.  And that's why you get seemingly weird behavior, like nulling the resonance when the source current is in a loop perpendicular to the burden resistor connection.

Similar fields manifest if you use a CMC differentially.  Which you normally do, in an EMI filter.  That is -- consider the common mode choke, using a toroid core, with two windings on opposite sides.  They are phased so the common mode is in phase (high impedance) while the differential phase is opposed.  Leakage inductance is fairly high in this configuration, i.e. the differential mode doesn't completely cancel out.  If you plot the fields from these, it looks very much like two bent solenoids, beside each other, opposing.  All the leakage field is external (since after all if it were in the core it would properly oppose!).

Maybe that's not too useful without a diagram... alas, my apologies.

Tim

19
Transformer (Ferrite Core) / Re: Mazilli ZVS Driver Modification Problems
« on: January 27, 2020, 12:54:42 AM »
A note about published timings -- these are often as much (or more?) a product of how they are measured, as a device characteristic.  In general, they're more for information than actual design use.

Consider two MOSFETs of equal Qg(tot), one logic-level type, one standard.  The logic level type will show somewhat faster turn-on times and significantly slower turn-off times.  Why?  The same charge has to be delivered to/from the gate terminal; the Miller plateau (where most of the switching is done) occurs at a lower voltage for the logic-level type.  When these are tested with same source/driver resistance (usually 4.7 ohms or something like that), the logic-level part is at a significant disadvantage -- less current is drawn during the plateau when it's at a lower voltage.

But that just means you can drive the logic-level part with some negative bias (if you happen to have a negative supply handy), and get symmetrical switching speeds.  Or drive it with a lower resistance source -- but be careful that even schottky diodes have significant voltage drop relative to a logic-level part, so you have less freedom to set rise and fall times independently.

For the IGBT, it might be tested at Vge(on) = 10 or 15V, and Vge(off) = 0V.  The threshold is below middle, 3-5V or so, so the switching speeds are asymmetrical.

It's quite common to drive IGBTs with negative bias, Vge(off) = -5 to -10V, in which case the switching will be symmetrical.

Modules tend to be rated at Vge(off) = -15V, for a full symmetrical swing; but beware that Qg(tot) may not be rated at the same condition.  This can make for a nasty surprise when designing the driver!

IGBTs work much like a MOSFET into a PNP follower.  Fast IGBTs have a low-hFE bipolar component, so a large fraction of load current flows through the MOS part, say 15-50%.  When the MOS turns off, the load current suddenly drops by as much, then the remaining bipolar current drops exponentially.  (This does actually act like diode recovery, internally.)

Slow IGBTs afford a lower voltage drop and higher current density, at the expense of slower speed.  This comes with a smaller MOS current fraction (maybe 2-5%?), higher hFE and slower turn-off (the bipolar current flow "drools" for some 100s ns, or even us for the higher voltage types).

Because current drops relatively slowly, IGBTs can dissipate a huge amount of turn-off energy, and are measured differently.  Whereas a MOSFET might measure its timings from e.g. 10% drain voltage to 10% drain current (inductive turn-off), the IGBT is measured to, say, 2% current.

Exact thresholds may vary by manufacturer, and I don't remember offhand if they usually list this in the datasheet, or if it's in a different document, or not disclosed at all...  Keep an eye out.

Tim

20
Of course, much stronger signals come with much louder ambients (ambiance? ;D ).  The usual effect is to get some of commutation (either the switching loop, so, a spike up or down during switching; or a fraction of the load, so, a squarewave superimposed on the reading; and of course whatever ringing from either source) as an error signal.  And yeah, the transient stuff you can filter out, but it brings into question: how representative is the signal really, and how much do you need to filter to clean it up, and since you're filtering, how does that impact your response time (for fault protection, or phase lock, or whatever).

Which for most power applications, should be pretty alright.  (Those damn CST-206s though?... ::) )

Tim

Pages: [1] 2 3 ... 7

* Recent Topics and Posts

post Re: Site Info desperately needed: http://www.stevehv.4hv.org/
[General Chat]
MRMILSTAR
Today at 05:14:40 AM
post Re: Russian voltage multiplicator stacking
[Voltage Multipliers]
davekni
Today at 03:54:03 AM
post Re: Building a bigger DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 03:48:54 AM
post Re: Building a bigger DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ritaismyconscience
Today at 01:03:12 AM
post Russian voltage multiplicator stacking
[Voltage Multipliers]
nix85
May 30, 2020, 11:50:10 PM
post Re: Site Info desperately needed: http://www.stevehv.4hv.org/
[General Chat]
Weston
May 30, 2020, 11:37:54 PM
post Re: Portable Q(uarantine)CW Tesla Coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Weston
May 30, 2020, 11:32:37 PM
post Servomex CO2 analyser
[Electronic Circuits]
Mads Barnkob
May 30, 2020, 11:06:18 PM
post Re: Site Info desperately needed: http://www.stevehv.4hv.org/
[General Chat]
Bradselph
May 30, 2020, 10:14:21 PM
post Re: Site Info desperately needed: http://www.stevehv.4hv.org/
[General Chat]
Weston
May 30, 2020, 08:33:05 PM
post Re: Site Info desperately needed: http://www.stevehv.4hv.org/
[General Chat]
Bradselph
May 30, 2020, 07:08:49 PM
post Re: Site Info desperately needed: http://www.stevehv.4hv.org/
[General Chat]
Mads Barnkob
May 30, 2020, 05:26:49 PM
post Re: Portable Q(uarantine)CW Tesla Coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
May 30, 2020, 05:25:45 PM
post Re: Site Info desperately needed: http://www.stevehv.4hv.org/
[General Chat]
MRMILSTAR
May 30, 2020, 04:31:14 PM
post Site Info desperately needed: http://www.stevehv.4hv.org/
[General Chat]
HighVoltageRulezz
May 30, 2020, 02:05:07 PM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
May 30, 2020, 09:46:46 AM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
klugesmith
May 30, 2020, 08:34:58 AM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
May 29, 2020, 11:22:22 PM
post Re: SSTC Micro
[Solid State Tesla Coils (SSTC)]
davekni
May 29, 2020, 08:53:35 PM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
klugesmith
May 29, 2020, 08:25:06 PM
post Re: CT performance investigations (Pearson and DIY)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
sgtraf
May 29, 2020, 05:42:45 PM
post Re: SSTC Micro
[Solid State Tesla Coils (SSTC)]
Magneticitist
May 29, 2020, 04:13:50 PM
post Re: Portable Q(uarantine)CW Tesla Coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Weston
May 29, 2020, 10:50:36 AM
post Re: SSTC Micro
[Solid State Tesla Coils (SSTC)]
jockoFergy
May 29, 2020, 08:46:27 AM
post Re: New projet OmegaDR
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
May 29, 2020, 12:00:26 AM
post Re: New projet OmegaDR
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mugi30
May 28, 2020, 11:40:37 PM
post Re: New projet OmegaDR
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
May 28, 2020, 11:29:00 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic Circuits]
petespaco
May 28, 2020, 10:33:50 PM
post Re: New projet OmegaDR
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mugi30
May 28, 2020, 10:07:59 PM
post Re: SSTC Micro
[Solid State Tesla Coils (SSTC)]
Magneticitist
May 28, 2020, 09:39:53 PM
post Re: 4kJ wire explosions from 2500uF/2kV Maxwell Energy Discharge Capacitor
[Capacitor Banks]
haversin
May 28, 2020, 03:55:56 PM
post 4kJ wire explosions from 2500uF/2kV Maxwell Energy Discharge Capacitor
[Capacitor Banks]
Mads Barnkob
May 28, 2020, 10:25:50 AM
post Re: SSTC Micro
[Solid State Tesla Coils (SSTC)]
davekni
May 28, 2020, 04:59:02 AM
post Re: MMC for a 32kvac load
[Capacitor Banks]
davekni
May 28, 2020, 04:32:26 AM
post Re: SSTC Micro
[Solid State Tesla Coils (SSTC)]
Rowdy
May 28, 2020, 04:12:23 AM
post Re: MMC for a 32kvac load
[Capacitor Banks]
Rowdy
May 28, 2020, 03:41:17 AM
post Re: MMC for a 32kvac load
[Capacitor Banks]
Rowdy
May 28, 2020, 03:40:25 AM
post Re: SSTC Micro
[Solid State Tesla Coils (SSTC)]
jockoFergy
May 28, 2020, 02:42:23 AM
post Re: Portable Q(uarantine)CW Tesla Coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
May 27, 2020, 06:21:39 PM
post Re: Improving IGBT gate drive
[Dual Resonant Solid State Tesla coils (DRSSTC)]
fnordest
May 27, 2020, 12:11:06 PM
post Re: Building a bigger DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Max
May 27, 2020, 11:51:19 AM
post Re: MMC for a 32kvac load
[Capacitor Banks]
davekni
May 26, 2020, 07:55:03 PM
post Re: Building a bigger DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
May 26, 2020, 07:40:48 PM
post Re: Working Principle Of Neon Transformer Circuit
[Transformer (Ferrite Core)]
iraquois
May 26, 2020, 05:12:42 PM
post Re: Building a bigger DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Max
May 26, 2020, 03:57:04 PM
post Re: XRay Tank- any ideas about what is inside
[Transformer (Ferrite Core)]
Mads Barnkob
May 26, 2020, 01:52:26 PM
post Re: Blew my first MOSFET, but it seems like it shouldn't have blown the way it did
[Solid State Tesla Coils (SSTC)]
T3sl4co1l
May 26, 2020, 11:52:33 AM
post Re: XRay Tank- any ideas about what is inside
[Transformer (Ferrite Core)]
HighVoltageRulezz
May 26, 2020, 09:40:52 AM
post Re: Blew my first MOSFET, but it seems like it shouldn't have blown the way it did
[Solid State Tesla Coils (SSTC)]
Magneticitist
May 26, 2020, 08:56:01 AM
post Re: MMC for a 32kvac load
[Capacitor Banks]
Mads Barnkob
May 26, 2020, 08:45:40 AM

SimplePortal 2.3.6 © 2008-2014, SimplePortal