Recent Posts

11

Test Equipment / Re: Spectrum Analyzer - Rigol DSA815

« Last post by 58kk90 on Today at 01:59:54 pm »

Guys, I have just picked up a used but mint looking  DSA815, in the licenses screeen, the only one I have is TG-DSA800 which I believe is the tracking generator as this has a tracjking generator installed that option is showing as forever, all the rest are showing as trial, time  left 0hr 0min 0s.

From the information screen, the unit has
Version of mainboard : 00.09
Version of radio frequency board FPGA : 00.05
Version of Digital board FPGS : 00:01.19
Version of Firmware : 00.01.19
Version of Boot : 00:01:04

From what I can see in this thread, I am stuffed to get the additional options enabled using the keygen as the trial time is zero for all the options, can anyone confirm that to be the case.
Obviously, having only just picked it up I don't want to turn it into a paperweight by doing something silly such as downgrading the firmware if that will not be of any help, but it would be really good to have the additional options enabled if possible.

Thank you.

12

Repair / Re: HP 3457A Opto-coupler/opto-isolator replacement

« Last post by peterkos2 on Today at 01:58:39 pm »

Great, thank you, it worked, now the multimeter works. When I go to measure resistance and connect the measuring cable in AUTO mode, is it possible that it takes almost 5 seconds and shows the result?

13

Microcontrollers / Re: SD Card reliability in SPI mode

« Last post by fchk on Today at 01:52:44 pm »

I wonder if you guys have experienced similar issues with SD cards using SPI? If so, if you were able to fix them or improve the reliability, what did you do?

Don't use them. Or use them not so often.

Look here:
https://www.microchip.com/en-us/product/23lcv04m
This is a 512kByte SRAM with battery backup pin. Write your data into that memory. When it's full or half-full, turn on the card and copy the data to the card, and then turn off.

Or better: use raw flash. Like this one.
https://www.alliancememory.com/wp-content/uploads/pdf/flash/AllianceMemory_SPI_NAND_Flash_July2020_Rev1.0.pdf
There is no controller it it. Its the raw flash. You are responsible for all bad block management, wear levelling etc. But this memory is deterministic. You always know what it is doing. SD cards are black boxes. They even don't have fixed timings. They may stop working for half a second at any time if they please to do so.

So:
Use SRAM to collect samples
copy large blocks from SRAM to Flash.

14

Programming / Re: Linux Dependency Black Hole

« Last post by mag_therm on Today at 01:51:07 pm »

Hi xvr,
Yes I intend  contact NXP if I have any problems with Debian 12.4 installation as that is its intended o/s.
Customer ? well I'm retired ham who bought a $40 Dev Board, that will carry some weight!

I used to program Siemens PLCs a long time ago. I regarded those PLC and the "IDE" as better, more advanced than the USA & Japan PLCs.

Any alternative for IDE on LPCX4367 if I have no luck with the MCUXpresso ?

15

General Technical Chat / Re: Is LinkedIn worth keeping?

« Last post by bd139 on Today at 01:48:25 pm »

https://old.reddit.com/r/LinkedInLunatics/

16

Test Equipment / Re: Siglent SDS800X HD 12 bit DSO's

« Last post by Antonio90 on Today at 01:46:17 pm »

Well, then I'll most likely have it on monday. I ordered through a spanish distributor, Isotest.

17

General Technical Chat / Re: Is LinkedIn worth keeping?

« Last post by madires on Today at 01:46:16 pm »

LinkedIn is great for training SPAM filters. They had so many data scraping incidents that my email address should be on most address lists. This is the only good thing about them, seriously. As with other social media platforms there's also scam and foreign intelligence services looking for opportunities. It might be useful for finding a new job, but be careful.

18

Beginners / Re: Help identifying these possibly RF/Microwave components?

« Last post by radiolistener on Today at 01:45:54 pm »

Last 3 are soviet military grade IC, they had strong quality control and testing and have good reliability and mechanical endurance. They are using gold plated pins and metal-ceramic housing.

But letter "K" at the beginning was used for marking general purpose IC, probably this is rejected military grade which is passed quality control for general purpose usage.

Soviet military grade components have ◊ symbol in its marking. So the last one has successfully passed military grade quality control.

And other two are produced the same as military grade, but didn't passed military grade quality control.

19

Dodgy Technology / Who cares about safety, feel the convenience!

« Last post by 5U4GB on Today at 01:44:10 pm »

Found on everyone's favourite crapvendor web site, a plug that any child, or possibly even a sufficiently clever pet, should be able to pop open to expose live mains wiring:



Look at how convenient it is, you just flip up the plastic cover, slide the wires into the plasticky Wago-like connectors, and without having to bother with awkward stuff like strain relief or screws to secure it closed you've got a mains plug ready to go.

20

Test Equipment / Re: SDS800X HD Actual Use Cases

« Last post by mawyatt on Today at 01:41:30 pm »

Added a few more plots.

#37 is a 47uF Electrolytic that measures 472.6uF (TH2832) @ 100Hz, with C Reference (1.01594uF) is Cr*10^(53.28/20) or 468.7uF @ 100Hz.

#39 is 1000uF Electrolytic that measures 997.8uF and plot shows Cr*10^(59.84/20) or 997.4uF @ 100Hz.

#41 is 47uF Electrolytic that measures 44.8uF and plot shows Cr*10^(33.12/20) or 46.0uF at 100Hz.

Edit: Technique also works with inductors. Since the inductive impedance is direct rather than inversely proportional to value there's no need to "invert" the Bode Plot. Follow the above analysis and insert inductive impedance rather than capacitive to show how this works. Of course one needs a Reference Quality Inductor which is usually rare, so we just used a small SMD 2.4mH as Lref, see #43. Note the Reference Impedance must be >> than the DUT Impedance for the "assumption" mentioned above to work, so a larger value inductor is required for Lref, rather than the smaller value Cref when plotting capacitance.

Anyway, details left for the interested readers and here's an example with a 100uH inductor using a 2.4mH reference. Inductor measured 100.5uH with T2830 at 10KHz and plot shows 96.0uH. Better result should be expected with quality reference!!


Best