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Metrology / E-bay AD588BQ references
« Last post by BradC on Today at 11:45:53 pm »
I've just had 4 E-bay special AD588BQ references arrive : https://www.ebay.com.au/itm/AD588-High-Precision-Voltage-Reference-Module-AD588BQ-without-battery/222382448519

If I read the data sheet correctly, the BQ should give 10V +/- 1mV. So maximum of 10.001V
The measurement sheet that comes with them says :
1 - 10.00282
2 - 10.00127
3 - 10.00156
4 - 10.00169

Measured with an unknown 34401A. So out of the box all 4 refs are out of spec. My rough measurements with an in-cal 3457a are within a couple of hundred uV of these measurements. I need to get them run up for a couple of days to measure them again. At the moment I have them powered with +/- 18VDC from a Tek PS503A, but my eventual aim is to use 3 15-0-15 transformers to float the references, then put them in series for a more stable 30V source, and then divide that down with a caddock divider to get 3V, 300mV & 30mV.

These could be anything, even factory rejects. But out of the bag they exceed the maximum tolerance specified in the data sheet.

Is my initial observation correct or have I missed a trap for young players ?

On the topic of the caddock divider : https://www.digikey.com.au/product-detail/en/1776-C6815/1776-C6815-ND, what would be a reasonable voltage follower to use to ensure the divider remains unloaded? Chopper stabilised op-amp?
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General Chat / Re: Why SpaceX Are Going to Beat NASA to Mars
« Last post by In Vacuo Veritas on Today at 11:45:01 pm »
There are no natural resources available that don't need mining/extraction. There is nothing of sufficient value on Mars that could be traded with Earth, apart from Mars rocks.
Well, for starters, Helium 3 would be worth shipping back to earth. It should be very abundant in Mar's regolith.
There's plenty of Helium 3 on the moon, makes no economic sens to go all the way to Mars for that.

You Space Nutters have odd definitions of "plenty". And just what do you think you need He3 for? Slightly lighter party balloons?
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Quote
Does XC8 AVR even allow C++
Although they have the c++ compiler executables included, I don't think they have it supported via the ide and do not include any c++ libraries.

I have no idea of gcc versions, but this what version it shows-
avr-gcc (AVR_8_bit_GNU_Toolchain_3.6.2_66) 5.4.0
Copyright (C) 2015 Free Software Foundation, Inc.


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Somebody told me, years ago, that such loops are intended as a thermal relief during soldering for heat sensitive devices.

Regards.
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Microcontrollers & FPGAs / Re: Practical guides to BCH FEC?
« Last post by philpem on Today at 11:35:52 pm »
I'm curious -- what is the significance of 0x4A and 0x83? (I'm guessing 0x4A is the generator polynomial?)

I'm trying to modify this for the (31,21) BCH code used by POCSAG. Looks like this would be fairly efficient to implement on an MCU, or at least have a predictable execution time.
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Metrology / Re: Cheap 10 MHz distribution amplifier - caveat emptor
« Last post by ArthurDent on Today at 11:35:02 pm »
David Partridge used an interesting and effective scheme to synchronize outputs on his divider board (no longer available) that could output several different frequencies that would all start at the same time. I have one of the boards he produced and it works great. Here is the description of the circuit that might be of help.

http://www.perdrix.co.uk/FrequencyDivider/
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Beginners / Re: Help me pick a desoldering iron
« Last post by tester43 on Today at 11:32:33 pm »
as "heavy duty" are you referring to power, recovery, overall strength of enclosure or which other aspect?
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Beginners / Re: beginner brain drain
« Last post by schmitt trigger on Today at 11:31:41 pm »
I think that whoever coined the phrase, "Growing old gracefully" needs is @ss kicked.  There is nothing graceful about it.  The love life wanes, the eyesight goes, the memory goes, errr, ah, what were we talking about?

And the SMT components are getting smaller and smaller, while the pulse becomes shakier and the eyesight poorer!
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Curious.  I cant say what is wrong with the 10.2 installation.       I have a 10.2 installation and everything seems fine.    Maybe try an external debugger (like Segger Ozone) to see if it is a driver issue or if something is just messed up with the IDE.
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Beginners / Re: Limit the output voltage of current sense opamp
« Last post by mikerj on Today at 11:30:04 pm »
Can you reduce the negative rail voltage to limit the negative swing to a safe value?
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