Recent Posts

1

Test Equipment / Re: HP 8566B Debug/Rebuild

« Last post by MarshallPlexi on Today at 04:23:11 am »

New attenuators in use and unless I totally misunderstand how the 8566B is running things, that's not a constant step in attenuation.


Thoughts?


https://youtu.be/RpouDlm22IY

2

Test Equipment / Re: New Brymen BM2257 Multimeter

« Last post by floobydust on Today at 04:00:44 am »

I find the low-end multimeters are usually running 8-bit clunker MCU's with the true-RMS done as a H/W DSP section AC-coupled and good to around 1.5kHz
Not sure what silicon-base Brymen is running in this BM2257 but AC freq. response seems to be 40-1,000Hz.

Sanwa pocket multimeters using e.g. Fortune Semiconductor FS9721-LP3 is just a basic rectifier 40-400Hz rated.

3

EEVblog Specific / AllPowers R1500 1500W 1150Wh LiFeP04 Battery Review + Teardown

« Last post by EEVblog on Today at 04:00:42 am »

AllPowers R1500 1500W 1150Wh LiFeP04 Battery Review + Teardown
https://iallpowers.com/?ref=cxufpsgb
Code: EEVblog10  for 10% off

4

Beginners / Re: PC restarts after shutting down

« Last post by squadchannel on Today at 03:25:09 am »

I think the CMOS battery is drained. Something similar has occurred before.

5

General Technical Chat / Re: Why does the US provide all critical electronic design knowledge to the world?

« Last post by vk6zgo on Today at 03:17:34 am »

I think this picture well explains the process of election

Which of those types of animals is an endangered species?

6

General Technical Chat / Re: A Little Semiconductor Related History

« Last post by RJSV on Today at 03:07:55 am »

   Especially enjoyed the INDUCTOR in integrated form;  square outline, and only 40% around the perimeter, (for best coil Q).

7

Test Equipment / Re: Hioki IM3570 LCR & Impedance Analyzer

« Last post by points2 on Today at 03:07:24 am »

hi KungFuJosh,

Given yours posts... you know a lot about this device & LCR in general.
I admit I have a limited use of my Shannon Tweezer LCR meter (bought because not too expensive, but so far : I admit I lack some basic knowlegde to get the most out of it).

When you have time... please anwser the following questions, to help "dummies" to understand how usefull a LCR-meter is : (or anyone that masters this topics like KungFuJosh :-) )

1. for what kind of inquiry, you need to use the Hioki ? in practice.
Is it vs PCB traces impedance ?
Is it just components on PCB measurement ?
Is it about trace impedance vs power delivery ? or signal delivery ?
I guess you use it for more fine measurement than a Shannon Tweezer user :-)

2. the Hioki extends to MHz range : how this makes a diff vs low end LCR-meter that don't go so high ?

3. related to previous question : what's the diff vs the results given by the Hoiki vs a cheap LCR-meter ?

4. using the Hoiki, is the limiting factor vs "fair results" => the fixture ? I mean : the way to measure matters a lot vs the results ?

5. as a dummy vs LCR-meters, when I see 5MHz MAX, my brain struggles to find how usefull such a tool can be when I deal with signals far above 100MHz...
Is this Hoiki relevant vs trace Z measurements when the signal is so far away from the "5MHz max" ?

I stop here. :-)
Anyone can reply to help the dummies.
And of course, anyone can urge the dummies to get more info here & there to be "less" dummy vs that topic :-)

8

Projects, Designs, and Technical Stuff / does PNP or NPN Make more sense in this welding circuit?

« Last post by coppercone2 on Today at 03:06:43 am »

2 replies on another forum say its a 04, the schematic someone made says its 06.

I am inclined to believe the schematic, but my memory of the event is shot. Basically I fixed a welding machine, but wanted to replace a few more parts near the damaged one, just incase. I replaced everything I thought was possibly related, then there was a explosion near this transistor. I am almost sure its supposed to be a 2n3906, and that a moron and a parrot lead me in the wrong direction, but I just can't be sure if there perhaps is a different problem.


This is a diagram from a welding forum someone drew




The transistor in question is Q3, which is a 06 in diagram


Is there any clues to tell me if a NPN could some how make sense in that point of the circuit?  Q3 is on top left, near the opto. R2 is the resistor that managed to explode, and it took out a IGBT!

9

KiCad / Re: How to best annotate components that are on the chassis and not on the PCB

« Last post by WillTurner on Today at 03:06:36 am »

You can have two (or more) boards (defined by their edge cuts layer) within the schematic, and two boards in the layout.

No, that is just plain bad advice.

Maybe so. My apologies in advance if you try this, and get into unrecoverable territory. Screenshot below of my current workspace, with what (?) a backplane, and six boards mounting at ninety degrees?
  We should all be trying to push the tools to find their limits. Personally, I am amazed at the stability of (V5) KiCAD.

10

Beginners / Re: [Schematic Review] Semi-automatic switching: Grid - EcoFlow

« Last post by leham on Today at 03:04:23 am »

Doesn't the ecoflow have a UPS function.
Why not just use that and put the important stuff you'll need in a blackout on its output.

The average apartment size there is 57 sqm, I'd take the mess of cables (that could be tidy) over back feeding your apartment and possibly introducing hazards to you or someone else