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Test Equipment Anonymous (TEA) group therapy thread
factory:
--- Quote from: unseenninja on November 18, 2024, 04:02:47 pm ---
--- Quote from: factory on November 09, 2024, 07:47:52 pm ---A question for those with the Peak DCA75 component tester, does anyone else have trouble with it testing 1N82x series reference Zeners? Mine fails to detect some of them, but these do test OK with the curve tracing software, note both the firmware & software are up to date.
David
--- End quote ---
Bit of a late reply, but my DCA75 detects a 1N829 as a simple PN junction with Vf=6.133V with both the previous and current releases of the firmware. So it's not just your example, it really does have a problem recognising these as Zener diodes.
--- End quote ---
Thanks for replying, I was going to add mine detects some 1N82x as a diode and some are not detected.
what I did notice is the parts from the same make/batch tend to test all the same, either as a diode or not detected.
All the 1N821 I have were tested last week, they all check within tolerance for voltage at 7.5mA, the flat line in the attached plot is a test lead not connected.
I didn't bother changing the Zener in the 6209A, after I realised it the reference was within the spec given in the manual.
P.S. did your DCA75 lose the sound with the current firmware (V23)?
David
factory:
--- Quote from: TERRA Operative on November 18, 2024, 05:10:54 am ---You could always go OLED like I'm doing with my HP gear.... :D
(Link is a few posts back)
--- End quote ---
For some unknown reason I don't think anyone has tried that for the Fluke 8050A, it's beyond me as it would need something like a programmed 'MCU board' adding, I prefer programming with discrete parts & tin/lead alloy.
--- Quote from: themadhippy on November 18, 2024, 12:18:25 pm ---
--- Quote ---lighting gel to tidy it up a bit
--- End quote ---
bit of lee 106
--- End quote ---
Yes something like that would help, but I need to build & wire up the replacement board first, there are other things to complete first. Actually I may have some red/or orange filters here, from spares that were bought on evilbay.
P.S. the case needs a little filler, to fix damage to the top edge of the front panel, thinking it would look worse if I was to paint it afterwards now.
David
Robert763:
--- Quote from: unseenninja on November 18, 2024, 04:02:47 pm ---
--- Quote from: factory on November 09, 2024, 07:47:52 pm ---A question for those with the Peak DCA75 component tester, does anyone else have trouble with it testing 1N82x series reference Zeners? Mine fails to detect some of them, but these do test OK with the curve tracing software, note both the firmware & software are up to date.
David
--- End quote ---
Bit of a late reply, but my DCA75 detects a 1N829 as a simple PN junction with Vf=6.133V with both the previous and current releases of the firmware. So it's not just your example, it really does have a problem recognising these as Zener diodes.
--- End quote ---
That's because they are not zener diodes. They are voltage references that do not have any forward conduction (below the breakdown voltage of the compensation junction.
factory:
Have a look at the 1N829A in the die pictures thread, it contains two diodes in series, one of which is used as the reference Zener junction & the other a diode junction connected opposite for temperature compensation, both junctions balance the temperature coefficient, the better grades are selected for lower TC.
https://www.eevblog.com/forum/metrology/more-voltage-references-die-pictures/msg4262863/#msg4262863
A datasheet for temperature compensated reference Zeners that are still available;
https://www.mouser.co.uk/datasheet/2/268/1N821_1N829A_1-3499699.pdf
Any diode could become a Zener (with current/power limiting), but most have too high a breakdown voltage to be of much use for that.
This begs the question, what type of regular (non Zener) diode has a volt drop of 6.2V, for the Peak to determine it to be a diode & not a faulty part?
David
ch_scr:
If you want to experiment, look at the 2dw232. Much the same idea as 1n82x, but "symmetrical" in construction (so either one can be zener / compensation diode), and with access to the "center point" as well.
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