Recent Posts

1

Projects, Designs, and Technical Stuff / Re: 3D printing company similar to PCBWAY for circuit board

« Last post by ataradov on Today at 11:40:10 pm »

Where can you get machined metal for the same price as 3D printed ones? I just tried with a basic half box and 3D printed one was $1.55 at 50 pcs. Machined aluminum one was $17.

You can probably get it cheaper with extruded stuff, but that limits your options quite a bit.

2

Projects, Designs, and Technical Stuff / Re: PC74hct4046ap Replacement

« Last post by PCB.Wiz on Today at 11:38:08 pm »

I keep wondering what that 1N4148 is even doing there? It's the oddest circuit I've seen.

It looks like a deliberate decision was made to run the PC2 output at not-quite-zero phase.
To balance the 4M7 drain resistor, PC2 will need a steady small pulse offset.

The circuit shows a CLK coming from elsewhere, so that likely dominates here, the PLL may be just for sampling purposes.

3

Security / Re: Microsoft repackages apps with a telemetry .NET wrapper

« Last post by SiliconWizard on Today at 11:37:39 pm »

I would say that Windows is a great modular spyware system which supports some operating system functions 

Yes! This is probably an hyperbole though! MS is only doing this to improve your user experience. Don't you want your experience to be improved?

4

Test Equipment / Re: Multimeter selection for production testing

« Last post by J-R on Today at 11:35:43 pm »

You didn't mention the voltage range of the device, and I assumed it had some regulation and could handle a 2V drop.  Maybe battery powered, such as nominal 4x1.5V or 12V.  But if your device runs at 3V I agree 100% with that value being a problem, in which case dropping to 0.1 Ohm might be an option.

100uV is trivial for a 6.5 digit DMM, 10uV is pretty easy with just some sanity checks, and even 1uV is possible if it's decent.  The DMM can autorange between 100mV/1V/10V without interrupting the supply.

Thermocouple effects are not much of an issue because you have the same number and type of connections going in as you do out.  But ideally still build a shunt configuration that is not going to get warm.

5

Beginners / Re: Checking for noise in resistors

« Last post by floobydust on Today at 11:35:14 pm »

From the era of tube gear, many signal tracers have a "NOISE" mode switch built-in. Example Heathkit IT-12.
That applies high voltage bias to the probe about 115VDC/1.7mA and with the audio amplifier you can listen to the result.
A noisy resistor or capacitor with bad dielectric can be flushed out. It was a common problem in the day.

Mr. Carlson's Super Probe has a "noise" switch but I think he's got it wrong and it's the actually RF probe mode.

6

Projects, Designs, and Technical Stuff / Re: PC74hct4046ap Replacement

« Last post by PCB.Wiz on Today at 11:31:28 pm »

Accordig to this post IR LED is even less noise!

https://www.diyaudio.com/community/threads/some-noise-measurements-for-leds-and-zener-diodes.35821/

In this application, it is not being  forward biased continually, so noise is meaningless.
Scope the pin, and check the waveform.

It is being used switching, with a narrow duty cycle, so you need low C, low ns and low leakage.
Some Toshiba parts give typicals of 1.6ns, 0.4pF @1V and  ~ 1nA at 5V / 25'C
 

7

Beginners / Re: Checking for noise in resistors

« Last post by coppercone2 on Today at 11:20:02 pm »

you can make a 300V battery using coin cells. You need alot, it needs a good 3d printer, and you need plastic tweezers.

8

Beginners / Re: Convert US standard 115V to International 230V

« Last post by Jwillis on Today at 11:17:22 pm »

Capacitor ESR decreases as frequency decrease and ESR increases as frequency increases. So whether it 50 to 60Hz or 100 to 120Hz it won't make any difference worth worrying about to output voltage ripple. This can be easily tested with any LCR meter with variable frequency. If your getting a huge change in value between 50Hz and 60Hz then the capacitor is nearing end of life anyway and needs to be changed.

9

Security / Re: Microsoft repackages apps with a telemetry .NET wrapper

« Last post by radiolistener on Today at 11:15:50 pm »

Actually you can.

Unfortunately Windows has a lot of different telemetry subsystems and some of them are hardcoded into kernel DLL's and cannot be removed or disabled. It has a bunch of hardcoded IP's and DNS addresses to collect the data, so it even hard to configure firewall to block them all.

I would say that Windows is a great modular spyware system which supports some operating system functions 

But you can still run it without telemetry if you turn off ethernet cable and wifi adapter   

10

Buy/Sell/Wanted / Re: The Bad Shopping Experience Thread

« Last post by ttx450 on Today at 11:15:08 pm »

Scam warning.  I was scammed in the sell/buyer thread by this person purchasing a Leader 3217.  It was finally resolved by paypal on my end.   I hope Admins will back list him, not sure where to post this?



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