Recent Posts

1

Microcontrollers / Re: Divide clock by 3 on a ATF16V8B

« Last post by langwadt on Today at 11:07:04 am »

Can you please tell me if this is doable, and how could I do it ? I can access to a Windows computer if needed.

Yes it is doable, with the caveat you have a 1/3 or 2/3 duty as mentioned above.

You need Wincupl, to compile boolean equations to JED and then a Device programmer to pgm the 16V8.
WinCUPL can run command line, which may help portability ?


If all you are doing is /3, you could look at other CMOS programmable dividers ?
eg the widely available HC161/HC163 can divide by 3 with an upper Qn connected to /LOAD, so the counter goes 14,15,0,14,15,0... for divide by 3.

Addit: If size matters, you could find a small MCU that has a CLK out option with /3 choice. Still needs programming, but it will be smaller than a 16V8 or CMOS counter.

double* and divide by 6?

number 4, http://xilinx.pe.kr/_xilinx/html/tip/sixeasypieces.htm

2

Projects, Designs, and Technical Stuff / Re: role of optocoupler for biasing drain of amplifiers

« Last post by john23 on Today at 11:06:38 am »

Hello XVR,could you give a practical numerical example with Tja & Tjc expression so i could see in what cases my MOSFET will be burned?
Thanks.

3

General Technical Chat / Re: Dumpster diving save VFD

« Last post by Miti on Today at 11:05:30 am »

From what device was it recovered?

Don’t know what it was. Check Noritake site.

https://www.noritake-elec.com/products/vfd-display-module/built-controller-vfd

4

Computers / Re: Format a 256GB pendrive with FAT32 using a windows 10 pc

« Last post by m k on Today at 11:02:20 am »

128 used to be legit sector size.

5

Projects, Designs, and Technical Stuff / Re: Build or buy? Multi-level vessel temperature logger

« Last post by mianos on Today at 11:01:12 am »

The term for the tube with a closed end is call a "thermowell". Normally they are stainless. The ones for brewing can be very long, 30cm. You can pick up all sorts of them from aliexpress.
Then, as BennoG says, I'd stuff a bunch of probes down them. Personally I'd much prefer proper 3 wire pt100 probes, you can also get them from "funny bunny"'s store.
He has the ones without covers, they are pretty easy to work with mechanically as the junction is only a mm or so. That would be very easy to wire and stuff.

This said, the normal MAX31865 is an spi device and you only get one probe per chip.  (I have good multiple board esp-idf drivers if you go this way and want them).

Your other option, DS18B20 would be much easier, they can all be run straight to your MCU with no driver board, they are quite precise. With .5 degrees of a PT100 based on my experience using them quite a bit. (They need pullups btw). The biggest down side would be getting a lot of them in a thermo well. 

ps, 0.1 is quite easy for the pt100. That's why I aim for.

I also have a pt100 on a bonded teflon tube. You could just fix these together and pull them apart for cleaning. Food safe, acid safe to the max. Not safe amongst forever chemical fear-mongers, unless you want top go past 550.

6

Projects, Designs, and Technical Stuff / Re: Corrosion on DIP pins

« Last post by tooki on Today at 10:59:56 am »

Turns out my Dad was over-watering plants in the general area and it dripped through the floor... yup... It's rust.

Hahahah my sister did the same thing to her Time Capsule (the little router/NAS Apple used to sell): it was on a shelf below some plants. The Time Capsule only has ventilation slots on the bottom, so water very slowly crept up, until eventually shorting the power supply.

Luckily replacement power supplies are readily available online (all appear to be salvaged) at low cost, so I just swapped it out.

7

Beginners / Re: The old "Replace blue LEDs with red LEDs" 7 segment question (74HC595)

« Last post by xvr on Today at 10:59:44 am »

> How much current can a small SMD Zener usually handle?

Milliampers, 10mA maximum (IMHO)

8

Other Blogs / 4.5-W 600-Lumen LED Emergency Light Circuit

« Last post by hesam.moshiri on Today at 10:59:40 am »

In this video, I have introduced an emergency LED light circuit using the SOT23-6 MP3202 chip. The board is compact and can be powered using a mobile phone USB Type C, a power bank, or any portable 5V power source.

Schematic & PCB: Altium Designer, Altium-365

9

Test Equipment / Re: Standardised Way To Test Oscilloscope Screen Update Rate

« Last post by pdenisowski on Today at 10:59:34 am »

High speed camera and frame anlaysis is one way obviously.

If "screen update" means "pixels changed" (assuming a continuously changing input), then I think that's the only way

We (R&S) actually make a visual monitoring system, mostly for EMS testing, that detects display changes (max speed is 30 frames / second).  One metric that it reports is how long something stops moving ("motion freeze")

https://www.rohde-schwarz.com/us/products/test-and-measurement/emc-test-software/rs-advise-visual-inspection-software_63493-149761.html
https://scdn.rohde-schwarz.com/ur/pws/dl_downloads/dl_common_library/dl_brochures_and_datasheets/pdf_1/AdVISE_bro_en_3607-3168-12_v0500.pdf

I assume a similar approach could be homebrewed by simply grabbing frames at a very high speed, doing a "diff" on them, and then measuring the time difference between "diffs"

10

Test Equipment / Re: Help me chose my pogo pin for THM Test Points on my PCB plz

« Last post by Kean on Today at 10:57:54 am »

Pogo pins are not normally used with that style of test point.  You are generally better off probing without a through hole test point, onto a bare SMT pad or maybe an open through hole pad.
There are various head designs like the crown point that can help probe a non-flat surface.

That style of test point are not so commonly used these days, except in R&D.  You would normally use a hook type test clip with them, like seen in the photo at top right.

Are you planning to use pogo pins from above or below the PCB?
If you were probing from above, you might be able to use a large concave (inverted cone) head pogo, like a P25-A2 or P100-A2.
If probing from below, it would depend on how much the particular style of test points used protrude from the PCB surface.