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Typical of mains browout (temp drop in V) due to large load eg industrial motor starting.

Get a mains V monitor ($15) see V during the event, use a UPS for affected lights.

Any industry eg auto body welders, food manufacturing, chemical plants nearby?

j
2
Metrology / Re: two LTZ1000 in "series" and attenuate to 10V?
« Last post by dietert1 on Today at 11:09:42 am »
If somebody makes an array with more parallel zeners in order to suppress zener noise, they will be approaching a situation where the amplifier deficiencies matter more.
Those 4x references like Fluke 734 or that Wavetek 7004N currently for sale at ebay for US$ 20 490 support averaging (parallel array mode). Don't know whether they can be used to generate 40 V. I remember in professional analog audio they used differential high level signals of up to +/-15 V, about a factor 100 more than the usual consumer audio.
Ideally a 4x reference should support 10 V, 20 V (2 x 2) and 40 V array modes.

Regards, Dieter
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Speaking from experience, I would suggest driving around your neighborhood, following the electric lines to the sub-station that serves your house. I wold not be surprised if you find some tree branches or vines that have grown into the higher Voltage lines. A tree branch swinging in the wind will have a natural frequency so your power can flicker at that rate.

Power companies just love to save money by cutting back on tree trimming.

Take some photos and send them to the power company. Threaten to sell them to a local TV station if they don't get on the ball.
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Didn't expect so many replies, thanks everyone. It's good to know many approaches as I struggled finding interesting solutions when doing my research.

I don't think I can achieve an adjustable output level using your method fourfathom, but maybe I'll borrow your schematic if I can't reach this goal. I sometimes wonder if it's actually worth the hassle to have an adjustable output anyway. Well, TTL high level is 5V so 3.3V may be a bit too low. On the other hand I don't want to fry low voltage CMOS circuits (even if I'm more of an analog/RF guy so I don't encounter that kind of stuff very often). So I'll keep trying to have a somewhat working adjustable level, even if the level range is narrow nor accurate.

Right now I'm still on the analog switch method (schematic attached) using SN74LVC1G3157 but I may look at the references suggested by PCB.Wiz. By the way, will the switch mess up the op-amps output or something like that?

Tektronix used it on most of their pulse generators.  They used the diode version for vertical channel switching in oscilloscopes which gives some idea of the potential performance.

Have you got any schematic? I don't know Tektronix products very well apart from their oscilloscopes so I don't know where to search.

Edit: nevermind, I found everything I needed on TekWiki.
5
Hi,

Using these devices daily for old batteries checks. My only complain to the original software is that it does not have any capability of command-line interface at least or a thermometer input as it is vital to see battery temperature for faulting batteries. And, otherwise, quite significant piece of characterisation of battery state...

Otherwise - in my opinion, original software is quite ok for the task.
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General Technical Chat / Re: Baltimore Francis Scott Key Bridge collapse
« Last post by xrunner on Today at 10:58:46 am »
Quote
how would people salvage all this in 3 days right in the middle of the river with no bridge
canoes

Didn't the ancient Egyptians move multi-ton obelisks on simple wooden boats?  :-DD
7
General Technical Chat / Re: Post a picture of a cat!
« Last post by woody on Today at 10:58:18 am »
I just hate it when she looks over my shoulder at something that isn't there.  There are not ghosts and there is nothing on my shoulder or behind me!
Are you sure? I'm not a believer in other dimensions but every one of my three cats exhibit this behavior regularly.  You would swear they see something where I see nothing special. Then another thing is that every now and then, while searching thoroughly, I fail to find a cat, only for it to appear a moment later with a face like: what? Probably just back from a fold in the Space-time continuum that they can see but I can't.
8
OK,

PROVE IT!

No proof, no tee shirt.



Well?  I guess you might call this a philosophical question, but, no matter the power source creating your DC power, it will eventually die meaning no longer a DC signal as it has an AC attribute.  (Heat death of the universe and all that...)  Even a permanent magnet's field fades over time, hence they are not truly constant.

Can we or the universe ever achieve an authentic 0hz unchanging charge with 0 AC characteristics?

Don't forget the other time direction.  It's not "DC" if it didn't already exist since the  beginning of the universe.  So we by definition cannot "create" a DC field.
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I am using Altium Designer 20.2.5 and trying to build a hierarchical design. There are two schematics: top level and sub level, as shown in the following figure (named Top Level):

What I expected was that all the PWM net names in the sub-level schematic would change properly (PWM1, PWM2...PWM8), but the net names don't change, as shown in the following figure (named SubLevel). Each channel has the same net name.


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Test Equipment / Re: Tektronix 2445B calibration
« Last post by flashthunder on Today at 10:47:31 am »
Thanks Calibrationfixture...this scope sat unused for several years. Except for the calibration errors on boot-up it's a very functional scope, having been used very little over its lifetime. However, while it was in storage the Dallas chip battery died so any cal data has been lost. I don't believe it to be a hardware issue as everything functions fine, my only issue it the firmware related error message when booting up. I was thinking that using another scopes data was a viable solution and you are confirming that. I have tried loading another scopes file (thanks Miti) but no success yet.
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