Home
Help
Search
Login
Register51
Repair / Re: Ksger T12 Sudden Death
« Last post by floobydust on Today at 09:17:26 pm »No, that's a LM337 which is intended for negative voltages. You could use a LM317 board, bare bones.
Recent Posts
52
General Technical Chat / Re: new propellantless drive company
« Last post by Nominal Animal on Today at 09:16:36 pm »Propellantless drives violate conservation of linear momentum, but not necessarily conservation of energy.
A violation of conservation of momentum in one reference frame would violate conservation of energy in another reference frame. Although if you are throwing out conservation laws I guess you might as well throe out special relativity too.
I'm not "throwing out conservation laws"; the one possibility I pulled from my backside could conserve both linear momentum and energy.
Let's consider two inertial reference frames, one before and one after some acceleration with a propellantless drive. In the first, the violation of conservation of momentum appears to increase the total energy, and decrease in the second. This is special relativity. For special relativity to hold, in actuality, the total energy must be conserved instead.
One solution to that problem is to couple the drive, somehow, to a larger system, so that for the entire system both energy and linear momentum is conserved.
If we consider warp drives like Alcubierre drive, they only seem to violate conservation of linear momentum. They do not, because the (let's say) "anomalous velocity" of the warp drive does not increase the linear momentum; it only exists as long as the drive is "active", and is actually due to the space contracting and expanding with the drive. (If we observed such a drive, we'd probably see an optical distortion caused by such a drive, but had no other "hints" that it wasn't violating conservation of momentum or energy.)
Now, I have not examined all propellantless drives to find out if they only seem to violate conservation of linear momentum but actually do not (either because of spacetime distortion or by coupling forming a larger system where both linear momentum and energy is conserved), or if there are other solutions to the conservation of energy in different inertial reference frames while violating conservation of linear momentum, for example via quantum-scale effects. Because of this, I prefer to err on the optimistic side, and assumed other ways might be possible. If I had preferred to err on the side assuming all of important physics is already known, I would have written something like "Propellantless drives only seem to violate conservation of linear momentum. They do have to conserve both linear momentum and energy, just like for example the Alcubierre drive does, to not violate physical laws."
I did expressly write I think the one discussed in this thread is extremely unlikely to be a real effect, but it has more to do with the physics models ("laws") that have survived the tests of new measurements –– including special and general relativity –– refining or extending previous models rather than replace them.
53
Beginners / Re: Convert US standard 115V to International 230V
« Last post by radiolistener on Today at 09:14:56 pm »You might want to plug the device into a Kill-A-Watt and measure the power consumption under full load. I suspect it won't be more than 1000 W, but this way you can measure it and find out.
I'm afraid that such approach is not acceptable for safety critical devices development because it don't guarantee that device will never consume more power under some specific conditions.
54
Other Equipment & Products / Re: Different bases on Amscope microscope
« Last post by Psi on Today at 09:14:26 pm »Any time you bump them the microscope shakes for ages.
So don't do that.
The trouble is you bump it every time you touch your face to the objectives.
55
Test Equipment / Re: Choosing between entry-level 12-bit DSOs
« Last post by BillyO on Today at 09:14:05 pm »Try it with a sweep. It seems that it occasionally (maybe between steps) resets to the base 30 MHz frequency.Yes, I found the glitching too.
56
Power/Renewable Energy/EV's / Re: Aussie Fast Charger Company Tritium Goes Bust
« Last post by floobydust on Today at 09:13:20 pm »It's a terrible happening and important to know really why the venture failed, rather than the old "blame the economy/market" excuse.
Lately I see a lot of green industry companies - top heavy with high-wage executives, going public with the associated high legal, accounting and of course marketing spending - then waiting for the investment bucks, grants to roll in, along with the unicorn. They're not (yet) profitable, high burn rate.
Meanwhile, the one lowly engineer is flogged to make world-class products ASAP. Or they'll just fake it like Nikola or Theranos.
It's all based on overhype, inflated unrealistic sales numbers, overpaid exec's, total focus on marketing, and the assumption that new tech is merely a crop coming in for harvest.
EV bus manufacturer ProTerra goes insolvent, municipalities have $100's million worth of buses that never made their claims for range or reliability in the first place- costing 2x that of a diesel bus, orphaned. The company closes down, all warranty obligations and performance grievances wiped and then it gets bought on the cheap by Phoenix Motor. It seems to be the MBA green business plan. Blame it on a sales downturn, the economy etc. etc. but no, it's really the original business plan was "to the moon" with no ground connection lol.
The green pullback is severe whiplash for these overdone companies I think.
Downturn - Tesla is getting trashed too, laid off 10% or 6,000 staff in California and Texas. Let's just blame the economy, not the Cybertruck fiasco, not the CEO, not the silly expensive products etc.
"Andrew Baglino, the senior vice president of powertrain and energy engineering, said on X that he had made the “difficult decision to move on from Tesla after 18 years”. This a bad omen.
Lately I see a lot of green industry companies - top heavy with high-wage executives, going public with the associated high legal, accounting and of course marketing spending - then waiting for the investment bucks, grants to roll in, along with the unicorn. They're not (yet) profitable, high burn rate.
Meanwhile, the one lowly engineer is flogged to make world-class products ASAP. Or they'll just fake it like Nikola or Theranos.
It's all based on overhype, inflated unrealistic sales numbers, overpaid exec's, total focus on marketing, and the assumption that new tech is merely a crop coming in for harvest.
EV bus manufacturer ProTerra goes insolvent, municipalities have $100's million worth of buses that never made their claims for range or reliability in the first place- costing 2x that of a diesel bus, orphaned. The company closes down, all warranty obligations and performance grievances wiped and then it gets bought on the cheap by Phoenix Motor. It seems to be the MBA green business plan. Blame it on a sales downturn, the economy etc. etc. but no, it's really the original business plan was "to the moon" with no ground connection lol.
The green pullback is severe whiplash for these overdone companies I think.
Downturn - Tesla is getting trashed too, laid off 10% or 6,000 staff in California and Texas. Let's just blame the economy, not the Cybertruck fiasco, not the CEO, not the silly expensive products etc.
"Andrew Baglino, the senior vice president of powertrain and energy engineering, said on X that he had made the “difficult decision to move on from Tesla after 18 years”. This a bad omen.
57
Beginners / Re: Convert US standard 115V to International 230V
« Last post by IanB on Today at 09:08:47 pm »You might want to plug the device into a Kill-A-Watt and measure the power consumption under full load. I suspect it won't be more than 1000 W, but this way you can measure it and find out.
58
Test Equipment / Re: Using SCPI with python via telnet to connect with a siglent scope
« Last post by eTobey on Today at 09:07:58 pm »your kommando function doesn't just send the command to the scope, it also returns the first reply by running self.lese_daten().
You're not doing anything with the data the kommando function returns.
This is actually not my kommando ;-). Just got that from the internet, and did not notice this. Should have actually looked more closer there.
Thank you
59
Dodgy Technology / Re: KCD-11 rocker switch from aliexpress is junk
« Last post by thm_w on Today at 09:03:38 pm »The thing is some suppliers with the exact same looking part might be great. But yeah these look cheap.
LCSC has some from 10c each that I'd probably trust more: https://www.lcsc.com/product-detail/span-style-background-color-ff0-Rocker-span-Switches_SHOU-HAN-KCD11-2P-R_C5884414.html (hundreds of options just picked the first one).
LCSC has some from 10c each that I'd probably trust more: https://www.lcsc.com/product-detail/span-style-background-color-ff0-Rocker-span-Switches_SHOU-HAN-KCD11-2P-R_C5884414.html (hundreds of options just picked the first one).
60
Other Equipment & Products / Re: Different bases on Amscope microscope
« Last post by KE5FX on Today at 09:03:05 pm »Any time you bump them the microscope shakes for ages.
So don't do that.