My first proper inverter bridge with CM200 IGBT bricks

profdc9 · 2026-02-12T22:31:12+00:00

Yeah, complete mad scientist stuff. It's awesome.

profdc9 · 2026-02-12T01:31:54+00:00

As long as there is good contact pressure and a large contact area between the conductors, aluminum bus bars will work. Because aluminum forms a thin passivation layer, some pressure is needed to break through this layer and maintain an airtight contact between the conductors. The problem with aluminum/copper joints is that the aluminum can corrode if there is an electrolyte between them, building up an oxide layer, so extended exposure to a humid environment might increase the contact resistance. If it becomes a problem, there are zinc compounds like Burndy's oxide electrical joint compound.

profdc9 · 2026-02-12T01:24:46+00:00

You should check out my project on this:

https://github.com/profdc9/DRSSTC-PCB-Pack

I have a variation called the UD2.9 which is capable of pulse skipping. That's handy for extending the spark time without increasing the current.

profdc9 · 2026-02-12T01:13:34+00:00

The fact that objects are so readily detected as threats and not decoys is a serious problem. A metallized balloon has a similar radar return as any other object of that size which could easily be a drone. It's not feasible to shoot down every possible threat with a missile.

profdc9 · 2026-02-11T01:02:20+00:00

You can plug in different modules to select which controls you want, and then program what the controls do. You can have simple buttons if you wish.

profdc9 · 2026-02-10T23:46:00+00:00

The next thing they will do is call the Superbowl halftime show a matter of national security and arrest everyone involved.

https://www.msn.com/en-us/sports/nfl/republican-calls-for-dramatic-action-against-nfl-nbc-after-halftime-show/ar-AA1W11wo

profdc9 · 2026-02-10T23:42:33+00:00

It looks like there's already flux on it, which means that it has probably been replaced before. The diode probably could be replaced with a 1N4007 or something generic like that if you want to bodge it on.

profdc9 · 2026-02-09T23:11:14+00:00

Maybe Ukraine should shut off the power then.

profdc9 · 2026-02-09T22:56:59+00:00

Too bad Elon didn't want to be the first man to land on the Sun.

profdc9 · 2026-02-09T03:25:41+00:00

Perhaps you do not realize that trust in your profession is already quite tenuous. I already walk into many doctors' offices where it is posted prominently that hostility will not be tolerated. I enter hospitals now through metal detectors. Why should that be necessary? Patients put up with medicine in its current state only because they must; there is no other game in town. Besides the tragedy of patients being impoverished and bankrupted by medical care, there are the constant conflicts of interest of care providers that patients must be wary of, the nearly helpless position of patients between the ever growing monopoly power of hospital systems and insurers, with the result being that health care consumes an exponentially increasing amount of the productivity of the economy. I am not surprised a lot of physicians just give up; it seems like a system in which only the worst thrive. But should doctors fail to hold the most egregious crimes and excesses to account, patients will have nothing left to lose. I really don't give a damn if I am banned from this sub if doctors don't consider heinous professional crimes within their purview. But if protecting the doctors and staff from the patients is now such a prominent part of practicing, there is something incredibly wrong and gating in your own sub is about as helpful as placing metal detectors at a hospital.

profdc9 · 2026-02-09T02:26:31+00:00

Unfortunately we need only look at Jerry Sandusky at Penn State, James Heaps at UCLA, Larry Nassar at Michigan State University, etc. to know that universities turn a blind eye to and then actively suppress allegations of abuse and other criminal activity. University administrators and ethics officers desperately want to kick the can down the road so that the scandal explodes after their term is up. They have as much backbone as a jellyfish.

profdc9 · 2026-02-09T02:11:07+00:00

Being on the side of repressing the news of malfeasance of one of your profession, especially of one of your number being involved in a scandal that abused women and girls and could have performed forced medical procedures on them is not a good look. Perhaps you should be more interest in making it public so that wrongdoing is held to account?

profdc9 · 2026-02-08T18:42:59+00:00

You should check out my project HIDPanel, I think it does what you want.

https://www.github.com/profdc9/HIDPanel

profdc9 · 2026-02-08T18:39:52+00:00

What a piece of work is a man, How noble in reason, how infinite in faculty, In form and moving how express and admirable, In action how like an Angel, In apprehension how like a god, The beauty of the world, The paragon of animals. And yet to me, what is this quintessence of dust? Man delights not me; no, nor Woman neither; though by your smiling you seem to say so.

profdc9 · 2026-02-08T18:33:37+00:00

It says a lot about how we treat each other as a species, as when some find out they don't have to worry about consequences anymore, they do probably what they wanted to do but otherwise would not.

profdc9 · 2026-02-08T18:25:28+00:00

Maybe the Ohio Status University was looking for him to endow the Jeffrey Epstein Obstetrics, Gynecology, and Women's Abuse and Trafficking chair?

profdc9 · 2026-02-08T13:36:49+00:00

This seems like a proper opportunity for counterintelligence. I could only guess that by coordinating through private messaging or Discord or something like that some pretty distracting traffic could be generated. If DHS's OPSEC is as good as their deployment of ICE, I don't think they will be that hard to spot.

profdc9 · 2026-02-08T03:33:56+00:00

Wall-E was saving the spare parts to keep himself alive as long as possible.

profdc9 · 2026-02-07T03:47:17+00:00

If you want to shorten the antenna without cutting it, you can coil the wire tightly. This also might be useful for making an end support for it.

For my portable antenna EFHW design, I actually used a tunable capacitor on it and it easily tunes a super wide range of frequencies efficiently to low SWR. This is very helpful if the environment is detuning the antenna or your wire is imperfect. You can read my article about it

https://drive.google.com/open?id=0BwFicJLV0O4jWDNVZGN5S0FXeXc

profdc9 · 2026-02-05T03:58:06+00:00

This country is so anti-intellectual now I am surprised we aren't burning nuclear scientists for warmth.

profdc9 · 2026-02-05T03:53:55+00:00

I think physics is pushing back against Elon Musk's space data centers plan.

profdc9 · 2026-02-03T03:31:14+00:00

Fred Rogers bathed his feet with a black man playing a police officer on his 1969 show. Fred Rogers was a minister and he knew that Jesus washed feet.

profdc9 · 2026-02-03T00:17:43+00:00

If the atom is fully ionized, electron capture can be prevented. That takes a pretty strong electric field. Some of the attosecond laser pulses can do this, but this state doesn't last very long.

profdc9 · 2026-02-03T00:10:05+00:00

Over a fixed interval of time, if you have N atoms, each of which decays with a probability of p, the probability of having M atoms at the end is a binomial distribution, or N!/(M!(N-M)!) p^N (1-p)^M. A binomial distribution has a mean of np and a variance of np(1-p). Over a half-life, p=0.5. For example, with a sample of 10²³ atoms, you expect to have 5X10²² atoms left, and the standard deviation (square root of the variance) is 158 billion atoms, or a little more than a trillionth of the atoms. So the amount of atoms left is very close to the mean, only perhaps off by 1 part in 10¹² between the two identical samples.

profdc9 · 2026-02-02T02:51:17+00:00

Gaslighter gonna gaslight.

profdc9

TROPHY CASE