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11
Metrology / Re: Advice/Experience for Keysight DMM Calibration?
« Last post by NANDBlog on Today at 02:48:27 pm »
no, uncertainty on calibration certificate is not your meter’s data sheet. the uncertainty is evaluation of how uncertain the reported measurement data is, usually it includes short term repeatability of your meter, finite display resolution of your meter, measurement standards uncertainty, measurement procedure uncertainty, tempco if relevant etc., in general it is limited by the class of your meter because finite resolution, intrinsic noise etc., you can’t get better reported uncertainty of 34401 than 3458, different class, even the cal source is the same 5730.

Quote
Specification (spec)
The warranted performance of a calibrated instrument that
has been stored for a minimum of 2 hours within the operating
temperature range of 0 to 55 °C and after a 60-minute warm
up period. All specifications include measurement uncertainty
and were created in compliance with ISO-17025 methods. Data
published in this document are specifications (spec) only where
specifically indicated.
12
Beginners / Re: HP 3457A Error Address 15
« Last post by sairfan1 on Today at 02:46:07 pm »
How should i test it that its workable? Or should i just replace it anyway?
13
hi there, there are a plethora of options when it comes to choosing the best cameras for youtube. The thing you should mostly focus on is creating quality content and for that I would recommend getting a medium range Canon DSLR. For more information regarding cameras for youtube read https://www.operaincinema.com/best-camera-for-youtube/.

more importantly you should also have a plan of action to promote your content. Remember content is King but promotion is Queen!

Good Luck


14
Anyone else remember Cramolin and Deoxit being pushed as Audiophool products back in the '80s.  >:D


I stick with Electrolube EML - It's sensibly priced!  https://cpc.farnell.com/search?st=eml
Deodit is still sold here in musical instruments stores.
15
Test Equipment / Re: Chinese GPIB DIY Adapter and how to use??
« Last post by Black Phoenix on Today at 02:38:13 pm »
That thing is a clone from the Prologix GPIB Usb -



Yes I know the image is not the same as the adapter in question, but by the looks of it it uses the same chips and drivers.

The manual that was in the folder was added as an attachment to this topic.

More info how to:

https://sites.google.com/site/prologix2/faq2
16
Test Equipment / Re: Chinese GPIB DIY Adapter and how to use??
« Last post by ebclr on Today at 02:37:23 pm »
This is the original seller

https://item.taobao.com/item.htm?spm=a230r.1.14.4.17482038IT8YsQ&id=565355186044&ns=1&abbucket=15#detail

The original version of fenrir is available at https://fenrir.naruoka.org/archives/000944.html

Fenrir original Github https://github.com/fenrir-naru/gpib-usbcdc

Prologix official website http://prologix.biz/gpib-usb-controller.html

Use the command to refer to Prologix related information http://prologix.biz/gpib-usb-6.0-faq.html


Driver and some available software links: https://pan.baidu.com/s/1i1Is4Mn2fG7fngyJAKWWog Password: pxmp

17
Repair / Re: HP8596E Spectrum Analyzer repair
« Last post by analogRF on Today at 02:34:40 pm »
Well, yeah I would not mind an LCD upgrade if there is such LCD module available.       Can you point me to it ?


In the meantime I installed the overhauled CRT assembly back into the analyzer, not much luck, the display is very dim but sometimes and intermittently comes to full brightness or even brighter than I'd think is normal. When it does so, is also out of focus. But mostly it is dim.

I have been working on this CRT assembly for a couple hours now and  measured a few voltages:

+60V rail measures +75V
-200V rail measures only -142V

I think this could be the problem. I replaced diode D3 and R76 but did not bring the negative voltage to -200V,  so I guess the Flyback transformer is toast.  :(

https://www.ebay.com/itm/NewScope-0Jr-LCD-kit-for-HP-8591E-8593E-8594E-8595E-8596E-Spectrum-Analyzer/133205624430?hash=item1f03ac866e:g:mUUAAOSwEgRdo8T7
18
Based on my memory of the discharge curve for an 18650, at 3.5V the battery is about 80% discharged, and voltage drops rapidly after that.  It's possible the buck/boost converter would give you a shorter battery life than an LDO.  I think that's particularly likely if your ESP32 spends any significant time sleeping (switching regulators are typically less efficient than LDOs at very low currents).

But you may find that you need an LDO that will provide more current than the MCP1700.  Nominally, 250ma should be plenty, but wifi devices can generate large current spikes when they transmit, and more headroom in the LDO helps deal with those.  Also, there's a Youtube video by Andreas Spiess on powering the ESP8266, and he ends up recommending a large (1000µF) electrolytic cap on the 3.3V line to prevent voltage drops caused by the spikes.

Hopefully those with lots of experience with the ESP32 can give you some good advice on this.

19
Test Equipment / Re: Fluke 289 Meter
« Last post by Gandalf_Sr on Today at 02:34:28 pm »
It has happened to me before - what I don't understand is why anyone would go to all the trouble of listing something, getting a buyer at the asking price, and then not shipping it.  Is there a scam angle that I am unaware of?
20
Vintage Computing / Re: How do I make a 8 bit computer?
« Last post by granzeier on Today at 02:33:27 pm »
Another classic book, which has been released by its author, is Jan Axelson's "The Microcontroller Idea Book" (http://janaxelson.com/files/microcontroller_idea_book.pdf) - it is actually being hosted on her web site.

The 8052-BASIC system that she describes can actually be pretty simple. Her first schematic (figure 3-1, page 24) contains only seven chips. If you have a TTL USB-to-serial converter, don't need to expand beyond 32K of RAM, and don't mind a slightly sloppy reset (use hers without the diode and 74HC14 inverter, it will work fine) you can build a BASIC computer with only four chips. Of course, Jan goes on and adds a bunch of additional stuff - the BASIC-52 computer can be expanded just like any other computer.
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