Recent Posts

1

General Technical Chat / Re: Russia and China to Build a Nuclear Plant on the Moon.

« Last post by tggzzz on Today at 09:20:23 pm »

The moon doesn't rotate, so no night or day.

Of course the moon rotates. Once a month.

The dark side of the moon is a music album, not any description of reality.

The moon did have a "dark side", but stopped having one on October 7th 1959.

Must have been a rough day.

So bad it was front page news around the world. Scared the USA witless.

2

Beginners / Re: Replacing SRAM IC with Flash

« Last post by mariush on Today at 09:19:58 pm »

at the most basic, four two position slide switches would work. But would bad user experience.

You could use  two buttons and a up/down counter logic chip like cd4510 or cd4029 or others. Some of these counters can be configured to output binary or bcd, or decimal ... in theory you can find bcd to decimal logic chips or possibly even some seven segment led  driver that accepts bcd input to show hexadecimal on a single seven-segment digit

But honestly a microcontroller would make sense as it could debounce a couple buttons (up down reset) and could also display the actual selected block on a two digit lcd screen or a couple seven segment digits or eink. ... example of raw lcd : https://www.digikey.com/en/products/detail/lumex-opto-components-inc/LCD-S2X1C50TR/469771

example of microcontroller with built in lcd driver : https://www.digikey.com/en/products/detail/microchip-technology/PIC16F19155-I-SS/7801934

with seven segment digits you could have the digits shown only for a few seconds after change, and then turn off digits if its an issue of power consumption. with some tiny red seven segment digits you could have 1mA per segment

The ram chip you mention is 10$ on lcsc, but you can get similar from digikey for under 2$, for example https://www.digikey.com/en/products/detail/infineon-technologies/CY62148G-45SXI/5247544 ... another example, 2.4$ if you get 10 : https://www.digikey.com/en/products/detail/issi-integrated-silicon-solution-inc/IS61WV5128EDBLL-10TLI/2799145  this one's also on lcsc https://www.lcsc.com/search?q=IS61WV5128EDBLL

If you hurry you could get 16 mbit sram chips for under 4$ each ... https://www.digikey.com/en/products/detail/infineon-technologies/CY62167GN-45ZXI/7362593   - these have up to 21 address pins (can be configured as 2M x 8 / 21 address pins or 1M x 16 / 20 address pins)

3

Test Equipment / Re: New Zoyi multimeter+oscilloscopes - ZT-70xS, up to 50MHz/250MSps (nov 2022)

« Last post by lchao on Today at 09:19:21 pm »

New, v1.35 FW is published on the d380 forum.
http://www.dt830.com/forum.php?mod=attachment&aid=NDU2NjJ8YWQ0YmU0MmJ8MTcxNDA3OTU3MnwwfDg0MDA%3D
It is mentioned, that the AUTO function was improved in this version.

4

Test Equipment / Re: Neutrik TP401 / MJS401D Service Manual

« Last post by 707dave on Today at 09:18:07 pm »

I too would be interested in a copy of the manual, I’ve a TP 401 and information is amazingly difficult to find for these units.

5

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.

6

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.

7

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.

8

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.

9

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.

10

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.