Recent Posts

1

Projects, Designs, and Technical Stuff / Re: Identification of two electronic components

« Last post by factory on Today at 07:14:27 pm »

Snubber was made by Daewoo, but rather unfortunate for them to use a part labelled BSE in a fridge. 
Other component labelled DSA looks like a resistor, but incased glass for some reason.

David

2

General Technical Chat / Re: Possible to trigger at battery explosions in pagers ?

« Last post by linux-works on Today at 07:11:04 pm »

remember the old screen saver about flying toasters?

well, dont plug in your toaster, either.

3

Altium Designer / Re: Altium ActiveBOM grouping ... Bug? User error?

« Last post by tooki on Today at 07:10:44 pm »

Not sure what the heck Altium is trying to do here, still, with a unique parameter per group it still cannot display a BOM correctly.  Any thoughts?

It absolutely can do what you want.

The cause is really simple: the Group by drop-down in the toolbar isn't where you control how the list is compiled.

Instead, in the Properties panel, in the BOM Items section, next to Component Grouping, click the Edit button. "Check" here means "evaluate this parameter for grouping". Anything that is not in this list and has the checkbox selected is ignored. Note that as you change grouping here, under the list, the total number of lines will change.

When you group with the Group by menu, you're just changing how the list is filtered, not how the list is compiled. (You'll notice that the total number of lines does not change.)

4

Microcontrollers / Re: Receiving UART data as hex - STM32

« Last post by DavidAlfa on Today at 07:09:27 pm »

Yep, just another bug caused by the second beer, always terminate C strings or be prepared for the nasty consequences!
Just joking, I'm a disaster without any "external" help

5

Test Equipment / Re: Show us your noise floor

« Last post by trackersoft on Today at 07:08:24 pm »

Tek 784A all inputs at 50 Ohm 1 mv

6

Projects, Designs, and Technical Stuff / Re: How to verify the amplitude of a basic 100MHz module

« Last post by enut11 on Today at 07:07:40 pm »

Hi @radiolistener. Plot is obviously flat but I am at a loss as to how this can help me cal my CRO. I am a babe-in-the-woods wrt to RF circuitry.
enut11

7

Test Equipment / Python class for ET54xx electronic loads: testers wanted

« Last post by thephil on Today at 07:06:50 pm »

Hi everyone,

I have written a Python class for remote controlling my ET5410a+ electronic load: https://github.com/philpagel/ET54.

It's still quite fresh, probably buggy and not 100% documented, yet, but I think it's time to ask for a little feedback. So if you have an electronic load from the ET54 series (ET5410, ET5411, ET5420, ET5410A+, ET5411A+, ET5420A+, ET5406A+, ET5407A+) and you would like to try the Python package, I would very much appreciate some test-reports.

I have a bunch of automated tests – even just running those and letting me know if anything failed would help a lot.

Thanks in advance.
   Phil

8

Projects, Designs, and Technical Stuff / Re: IGBT Linear operation

« Last post by DavidAlfa on Today at 07:04:05 pm »

But - Do we agree that continuous power dissipation is just that, no matter what?
Yes, I perfectly understand surge/peak power, meant to be a small, low duty occurrence, let's say 1000% of the of max continuous power, lasting 20ms every 1s.
But "100W continuous power", to me it means "This device can dissipate 100W 24/7 below a defined Tj limit".
No matter if it's a small array of IGBTs or whatever, continous power should account for hotspots and manufacturing tolerances, some parts migh be extremely well bonded and tolerate 200W, while the worst only 130W.
Apply a safe gap and certify for 100W.

9

Beginners / Re: BM786 continuity beep not latched

« Last post by J-R on Today at 07:02:43 pm »

I personally don't like the scratchy sound either.  One solution: Dave can offer firmware version flash options in his store at an extra charge.

10

General Technical Chat / Re: Possible to trigger at battery explosions in pagers ?

« Last post by tom66 on Today at 07:01:14 pm »

Another interesting thing is the large number of simultaneous activations - is the pager network even capable of broadcast/multicast?
AIUI the way these usually do power management is they synchronise with a fairly slow timebase from the infrastructure, so they know when to wake up to check for transmissions - maybe once per minute or so. I don't know if this is typically synced over the whole network, but seems likely to avoid pagers having to track changes  of local base-station. Pagers are usually receive-only, so all messages are broadcast to all locations.
I wonder if there maybe was also a compromise of the infrastructure to send a broadcast message, or possibly even a fake radio transmission spoofing the actual network - is there any report of how wide the affected area was ?

Realistically even if it was bulk SMS (or whatever equivalent is used) to all the pagers, the messages would arrive within around a minute of each other - the only exception might be for devices out of range of signal.  With the commotion in an attack like this, I doubt you need true synchronicity, a few minutes is fine, no one will put the puzzle pieces together until later.

An attack like this is worth more than the injuries and deaths caused to their enemy (and of course the collateral damage) - they've made it so the enemy can't trust their supply chain.  It'll disrupt their equipment availability for months.  Everything will be suspect, every laptop, drone, phone, pager etc. will need to be disassembled to check for tampering.