Recent Posts

1

Test Equipment / Re: SDS800X HD Actual Use Cases

« Last post by Antonio90 on Today at 03:24:18 pm »

Yes, it's the highly asymmetrical input capacitance of the DMM +- inputs when measured to ground reference

The DMM - input has significantly more capacitance to ground than the + input, so when the pulse generator is reverse connected its' output "sees" a much larger effective capacitance thru the DSO input ground.

Best,

I didn't know that at all. Thank you very much!

2

Test Equipment / Re: Keithley 2231A-30-3 Communication

« Last post by simba15 on Today at 03:24:17 pm »

interesting!

I probably fried it with standard RS232 levels as it stopped responding at some point. ( duh... it says (TTL) lol)

I have 10 or so of them so I may try again with 3.3v levels.

Thanks.

3

Test Equipment / Re: Tektronix 2465B oscilloscope teardown

« Last post by MarkL on Today at 03:24:16 pm »

I said...

...
I will look to buy an A5 SMD board when I can find one for cheap, or if anyone has a working spare to loan me in the US for a few weeks, I promise to return it unscathed.

Actually, a broken one is ok too, as long as it boots.  I know these SMD boards can have analog and other issues from leaky capacitors, but it doesn't matter to get the NVRAM utility written.

4

General Technical Chat / Re: Do you think an LED is a resistor?

« Last post by Kim Christensen on Today at 03:22:39 pm »

This is not about the naming per se, it is about the fundamental nature of a diode from the point of view of the circuit. All it does (neglecting secondary effects) is offering a resistance.

Now you say it... yet your poll asked this:

Is an LED a resistor?
No. It has a different name, so it is not a resistor
Yes. It is a resistor, just not an ordinary one

You don't seem to realize that no one has an issue with a LED, or any other device, having resistive properties. We have an issue with you calling it a type of resistor.

resistance vs resistor 

5

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

« Last post by BillyO on Today at 03:22:36 pm »

I guess you are then "featuring" it in one of your videos pretty soon huh? 

That might just happen.

6

General Technical Chat / Re: Do you think an LED is a resistor?

« Last post by ebastler on Today at 03:22:23 pm »

Seriously, all this seems to point to a broader problem than I had thought. People here seem to have a problem in understanding set inclusion.

The even broader problem seems to be that people here, including yourself, have way too much time on their hands. 

7

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

« Last post by BillyO on Today at 03:21:47 pm »

I think you will like your new scope.  It was definitely a step up for me going from an old HP 54600 100 MHz 2-channel digital scope to a Siglent SDS814X HD.  And if/when I need it, I can *cough* upgrade *cough* to 200 MHz.  And I only got the 100MHz model because all the cheaper models sold out quickly...    I am glad I waited for the SDS800X HD to be sold in the west instead of getting the SDS1104X-E or SDS1204X-E.

It will be replacing my SDS1104X-E, which BTW is a fantastic scope.  The main reason is the 12-bits so I hope there are not too may quirks with it as there are practically none with the SDS1104X-E.

8

PCB/EDA/CAD / Re: Looking for CADSTAR pcb Uplaod Program

« Last post by Doctorandus_P on Today at 03:21:22 pm »

Not a direct answer, but if you have Gerber files available, then maybe KiCad is an option.

In KiCad you can re-create a PCB from a set of Gerber files. This process is not "instant", but you can recover a lot of information, such as PCB outline, mounting hole locations, all tracks, locations of footprints (implied in endpoints of tracks). There is no concept of footprints or pads in Gerber files, but when you place native KiCad footprints on the end locations of tracks, the re-creation is pretty good. As an estimate, an euro-sized (100x160mm) PCB will take approximately half a work day to convert.

For schematic (re) entry, there is no automation, but re-entering a schematic from a .pdf or printout is much quicker then redesigning or reverse engineering a schematic.

9

Microcontrollers / Re: RIP Z80

« Last post by peter-h on Today at 03:20:49 pm »

I started on the Z80 too. A great chip and really versatile in its time.

Today, most embedded stuff (except low end) is done in C and if the clock is fast enough the CPU architecture becomes almost irrelevant. And those who cut their teeth on the Z80 are mostly retired now.

And few of the original products will be selling today; I still nominally sell a Z180 based box designed in 1991 but the volume is very low. There are still GA avionics (like the JPI EDM700 family) which use the original Z80, EPROM, SRAM but their sales will be very low too, even in that extremely slowly innovating field.

How long a product can run is always a fun debate but the truly original DIP40 Z80 must have virtually ended. Even in the military sphere, things have moved on. The other day I saw the internals of the Javelin missile; a 30 year old design but still current on the Ukraine battlefield, which uses all kinds of expensive chips.

Littelfuse owning Zilog is the ultimate insult; a shit company making boring stuff owning a one-time real innovator.

10

Jobs / PCB Designer for sensor board with 4-20ma output

« Last post by pcbsensor on Today at 03:20:16 pm »

Hello,

I'm seeking a PCB designer to help with a brand new project to convert a voltage signal coming from a sensor into a proportional 4-20ma output. 
The PCB will be used in an industrial application.

The candidate should have knowledge of analog and digital circuits, power protection of the circuit, voltage step down and ideally have worked with integrating sensors in the past.

PM or e-mail me with your portfolio, CV or resume.  Also send your hourly rate, location and availability.

I look forward to speaking!

Thanks!