Recent Posts

1

Test Equipment / Re: Siglent SDS3000X HD and upgraded SDS1000X HD

« Last post by hpw on Today at 07:27:15 am »

The new to come 6&8 GHz models ?

First time I see BW references inside Siglent's FW going up to 16GHz !!!

This means, any 20..40Gs gear to come. Than we go with Bodnarpulse to the real 30ps risetime 

Requires any better based oscillator & synthesizers as in fs... just look at LeCroy HD series. To get any trusted Jitter figures.

Already available. 
https://siglentna.com/product/precision-frequency-reference/

Any trusted or valid company would provide any PN figures of the OXCO. In addition any ventilation as vibrations from the gear will reduced the performance of the OXCO to death.
This means also, double oven would reduce the any environment temperature changes.

IMHO, it looks like cheap AliExpress thinking's as no valued gear. While even no performance/improvements & data's provided. 

Hp

2

Beginners / Re: 5V buck converter debugging

« Last post by Vovk_Z on Today at 07:25:20 am »

I guess it can't work as intended with low input voltage, and even can be damaged (becuse it can't operate). So you have to feed it with needed intended voltage or nothing.

3

Repair / Re: Advice on aperture repair on camera lens

« Last post by ApertureScience on Today at 07:22:26 am »

You could start by submerging the assembly and working it a few times. Reassembly can be quite tedious. If the material permits you can also try acetone, be very careful.

4

Projects, Designs, and Technical Stuff / Re: what certification is required to sell electronic products?

« Last post by selcuk on Today at 07:15:58 am »

As suggested, you will need some certification. But you need to pay attention to the technical aspects as well. This is the datasheet of the module:

https://www.espressif.com/sites/default/files/documentation/esp32-s3-wroom-1_wroom-1u_datasheet_en.pdf

If you check the module picture and then read the schematics on page 27, you will observe that there is only an RF shield and an ESD diode on 3.3V net for EMC purposes. They are something but you will again need to spend time for the design and tests of the end product.

5

Test Equipment / Re: SDS800X HD Bug Reports + Firmware

« Last post by eTobey on Today at 07:12:54 am »

I thought it is quite obvious what is happening. I have edited that post.

6

Repair / Re: Korad KA3005P power supply faulty/repair

« Last post by thphuong1978 on Today at 07:12:18 am »

Hi everyone.Who do it success?.
I try with coocox+jlink but no luck.
Mr.Tony Mach Can you send me .bin or .hex
to flash mcu directly sir.My mcu dead
Now I bought new mcu already.
   Regard.

Well, I reached a crucial point with my firmware for my KA3005: The basic functionality (and everything needed for this) is working!!! I can adjust voltage and current, and the respective values are displayed! 

It took a little longer than I thought to reach this point – but hey, I do this in my spare time, for free and for fun (at least my tortured sense of fun)…

There is a metric ton of caveats attached to this firmware:

• This works on my KA3005 - other hardware revisions may have critical differences (There is much strangeness in the schematic…)
• AFAIK one can not read out the original firmware - so once you overwrite the original firmware you can not go back
• There is no calibration routine, the calibration values are hardcoded
• CooCox and the debugger are strange… Relays sometimes switch when you load new firmware – this contributed to me having once shot the power transistors  The firmware was broken, so I wrote a new firmware, which broke the PSU - talk about irony… (But hey, I bought new transistors, fixed it  and learned an important lesson: Do not leave a load like a 12V 100W bulb attached when the debugger is attached - detach any bigger electrical load before you load a new firmware. A 230V 50W bulb on the other hand is fine.)
• I make mistakes (I once reached a peak value late at night of 2 bugs per 1 line of code) – this also contributed to the aforementioned incident where I shot the power transistors  But now the switching of the relays should be solid.
• Memory is not implemented (M1 to M5 not done)
• The interface to USB/serial is not implemented (my PSU model is without the interface board, and one would need to reverse-engineer the protocol, so this maybe will never happen)
• The keys are not debounced
• No LOCK, no OVP, no OCP
• The LEDs flicker under certain conditions (I know how to fix that, but haven't had the time to do it…)
• Haven't fully figured out the temperature-ADC yet
• Fan is switched on with the output, and runs aways with full speed while output is on
• Other problems I forgot
• Source code needs clean-up
• No warranties whatsoever
• No buzzer

But there are also good things:

• No buzzer
• IMHO the adjustment of voltage and of the current is nicer in my firmware (and I might improve it even further by a little bit)
• Considering the power rating of the transformer, and of the transistors, I think it could be possible in future to "overdrive" the PSU and output more voltage, or possibly even more current, under certain circumstances (if one stays within the ratings of those components)
• One could implement custom behaviour (e.g. "soft start", or specialized battery charger, or or or …)
• One could add an output relay, or maybe even an MOSFET as an output switch

If you want to use this firmware, you need CooCox (I used 2.0.7, but other versions should do fine). I had to add cmsis_core, M051_BSP_CMSIS_V300_001 and C_library to my project (the C_library might not be necessary - the boilerplate I used needed it, but I haven't checked if I still need it).

Sorry, no pre-compiled binary from me, no turn-key project – if you want to use this experimental firmware, you need to know what you are doing. Have fun tinkering! 

I might continue working on some of the missing features, but I do not promise anything. 

bạn đã làm thành công chưa ? có thể chia sẻ mình file hex được không ? xin cảm ơn !

7

Microcontrollers / Re: Powering an STM32F103C8T6 With 12 Volts?

« Last post by RoGeorge on Today at 07:09:28 am »

If the microcontroller board doesn't draw too much current, a resistor and a Zener diode can be a good enough voltage regulator:


Image from:  https://en.wikipedia.org/wiki/Zener_diode

8

Dodgy Technology / Re: Is the market flooded with fake dangerous solar cable

« Last post by eTobey on Today at 07:09:09 am »

Got a cable from a solarcable brand K**. Had 80 strands with 80x0.28mm, which comes out at 4.92mm².

I checked on other cables i have bought (only one is a solar cable)(Germany):
4 out of 5 were wrong crosssections, by about 20%. 

9

Beginners / AC brushed motor, caps & inductors

« Last post by NeilP on Today at 07:02:30 am »

I have just started tinkering with old Singer sewing machines, and had a problem with the capacitor in a carbon stack speed controller
https://www.eevblog.com/forum/repair/carbon-pilestack-sewing-machine-foot-control-emi-suppression-capacitor/

I read the above and it got me thinking about the original AC motor.(1940’s machine)

It does produce a little interference / crackling on my radio in workshop..  I run an old Amateur Electronics circuit valve amp I built 40 years ago at school .. 


So I looked at original AC motor and as far as I can see, no caps or inductors for any sort of suppression.  Many of the sewing forums advice is ‘just remove them, they were for the days of analogue TV & AM radio’.   So possible these have just been removed.

But… my theory knowledge in electronics is totally zero.. 

So please can any one tell me how / what values I’d need to fit some suppression to this little carbon brush AC motor.  240VAC 75 Watt.

Might do the other pale colour motor too once black one done.


Thank you.

10

Computers / Monitor VGA PC detection

« Last post by Arty.lv on Today at 07:00:23 am »

Hi.

I have a following situation - I have a PC test bench monitor (large digital signage display) with all the video inputs one can have, HDMI, DP, DVI, VGA, Composite. But VGA input is only via DVI connectors analog pins. Since I want all the input cables connected permanently, so they are always ready when I need them, I bought a simple splitter - DVI to DVI and VGA (https://www.amazon.de/gp/product/B07KXSSQFM/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1).
The problem is, DVI input works only when VGA cable is also connected to a PC. It can even be a different computer. With single DVI->VGA or DVI->DVI cable everything works fine. My first guess was that the splitter has some missing grounds on the DVI input connector, but grounding all GND pins on VGA side did not help. Any ideas what signal it might be missing, ond/or how to make a terminator for vga cable, so the display thinks there is a PC connected to it?