Recent Posts

1

Projects, Designs, and Technical Stuff / Re: (Yet Another) DIY Multislope ADC

« Last post by NNNI on Today at 05:36:17 pm »

There's probably a better way to handle that - push rundown to the second PIO instance with a lower clock divider. That way, the PIO instance that handles multislope runup can be run at a reasonable clock speed, and the rundown PIO instance can have higher resolution.

However, that brings me to the question: what's the advantage of rundown vs reading residue using an ADC?

2

Projects, Designs, and Technical Stuff / Re: Identify an old (mid-1970s) 10-bit ADC

« Last post by ballen on Today at 05:36:04 pm »

As I recall it was a module, one of those black potted things with lots of pins, both Burr Brown and Analog Devices made many components in that style in the 1970s and 80s.

I'm trying again for a more reasonably-sized picture and the correct alignment.

3

Beginners / Re: New multimeter, is the thermometer good or better standalone?

« Last post by Gyro on Today at 05:34:08 pm »

Welcome.

I find separate is better. This leaves the multimeter free for use at the same time and broadens the choice of available meters. Separate thermocouple thermometers tend to be pretty much as accurate as the multimeter function. The low cost TM-902C has been around for decades now, I don't think they are manually adjustable like the early ones but are probably still good enough. I haven't checked which other ones are available these days.

4

Test Equipment / Re: Tek 2465 Horizontal Sweep Issue

« Last post by Orange on Today at 05:28:09 pm »

There is a good service manual available here https://w140.com/tekwiki/images/8/8b/070-3831-00.pdf
It has a flow chart for diagnosing the sweep circuit on page 283

5

Test Equipment / Re: Looking for a replacement general purpose oscilloscope for home use

« Last post by Kosmic on Today at 05:24:47 pm »

I unfortunately don't have the change log.

6

Test Equipment / Re: Looking for a replacement general purpose oscilloscope for home use

« Last post by joeqsmith on Today at 05:21:46 pm »

On the 7300a you can slow down calibration and disable temperature related calibration. I guess this is not available on all models.

Similar to the WaveBluder.  I leave it on as it does me no good.   Autocal on this scope takes maybe 1 - 3 seconds.  Basically a life time.

I have been using firmware 7.6.1.1.   Guessing this was from 2014, as it appears I archived it.  So if you decide to check the change log, it at least gives you a starting point. 

7

Beginners / Re: Dimming signal 0-12V from microcontroller (logic level to 12V PWM)

« Last post by Zero999 on Today at 05:21:44 pm »

The MCP1402 appears to be fine for just level shifting the 3.3V to 12V. It's possibly a bit overkill. A single BJT will probably do.


^{Level shift bi-direc BJT 3.3V 5V.asc}

8

Test Equipment / Re: DER-EE DE-5000 ESR zero measurement problem.

« Last post by TA3UIS on Today at 05:21:13 pm »

I connected 3 pieces of 1ohm parallel resistor in series to a 10,000uf capacitor. ESR measurement was successful.
What would this measurement reveal?

Is DE-5000 good or defective?

9

Test Equipment / Re: SDS800X HD Wanted Features

« Last post by eTobey on Today at 05:20:36 pm »

Why not fill the memory, so I can trigger on an interesting event and then scroll back and forward to see what happened before and after?

This is comething i never missed currently, but what my cheap handheld scope had. It might be technically only possible/easy to do for after the trigger though.

But then it would need a dedicated mode/option for it, since it is not always wanted.

10

General Technical Chat / Re: Cheapest way to get date/time from GPS

« Last post by nctnico on Today at 05:16:36 pm »

There is a german paper here: http://cadt.de/dieter/dcf/Praezisionsfrequenzmessungen.pdf
In Figure 12 you can see the 10 ** -11. This doesn't mean there was a determination of time to 10 psec, but the clock speed (in that case the rubidium oscillator) could be calibrated to that precision using DCF77. In my tests i actually saw agreement between a GPS and DCF77 (resp. the disciplined oscillators) at the 2E-12 level. Maybe they are using a GPSDO at the DCF77 station.

But as I understand it, that is frequency synchronisation only, not time.