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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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4th Sep 2022, 3:14 pm | #81 |
Dekatron
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Re: How would we design electronics to last 100 years?
Last time I studied this it looked to me that what the manufacturers mean by its "life" is being in specification. So after the stated number of hours it doesn't necessarily go bang - it may just mean it has drifted in value so much that it isn't what it written on the side. But many components in circuits don't need an accurate value so this is often not important.
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4th Sep 2022, 3:28 pm | #82 |
Dekatron
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Re: How would we design electronics to last 100 years?
In modern electrolytics, the lifetime is defined at 105 degrees ambient (which has already been pointed out, I see now) AND maximum allowed ripple current. For every 10 degrees less, the lifetime doubles. Reducing the ripple current will also result in a significantly longer life. Low ESR electrolytics allow for higher ripple currents at 10kHz to 100kHz than traditional types so are especially suitable for such applications.
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4th Sep 2022, 8:17 pm | #83 |
Nonode
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Re: How would we design electronics to last 100 years?
Some other things that might help, depending on the particular application of said electronics.
Avoid straining any PCB during manufacture as this can lead to component failures. MLCCs on a PCB are particularly prone to this. As an example, it's quite common to snap PCBs out of a panel. It's much less likely to cause a problem if they are machined out. Ensure the finished PCBs are clean. Flux or other residues can absorb atmospheric moisture and become conductive causing dendritic growth leading to shorts or partial shorts. Conformal coating can help with this, but also make it worse. I have personally seen extremely early life failures caused by flux residue that ultimately caused a MOSFET drive to oscillate, and the MOSFET overheat and cease to exist. |
4th Sep 2022, 8:36 pm | #84 |
Dekatron
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Re: How would we design electronics to last 100 years?
Duncan touches on 'breakout' PCB's. It made me cringe last week when i had to separate 5 charging modules from each other by force. They did of course have a V slot on either side, but even so..
dave |
4th Sep 2022, 11:07 pm | #85 | |
Pentode
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Re: How would we design electronics to last 100 years?
Quote:
FYI This is a video of my "1924 Sterling Anodion" single tuned circuit radio receiving Radio Wales on 882 kHz from the Washford transmitter. https://youtu.be/3ZxiaJvIb1g This radio is almost 100 years old and still functional. Last edited by Catkins; 4th Sep 2022 at 11:12 pm. |
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4th Sep 2022, 11:21 pm | #86 |
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Re: How would we design electronics to last 100 years?
The need for electronics is likely to have changed significantly if the last hundred years is any guide, so current electronic stuff is likely to have become museum exhibits. Still, it would be nice if they could be demonstrated working, just to show what we had to put up with back in our era.
David
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4th Sep 2022, 11:37 pm | #87 |
Dekatron
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Re: How would we design electronics to last 100 years?
Thanks very much for the info on the effect of temperarure on electrolytic capacitor life. My Icecrypt STB is mounted on end on the side of its TV, reminiscent of how our Band III convertor was mounted to get ITV, so should have good thermal convection via the ventilation slots in its sides.
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5th Sep 2022, 8:41 am | #88 |
Heptode
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Re: How would we design electronics to last 100 years?
Not exactly electronics, but close:
Oxford bell
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5th Sep 2022, 9:59 am | #89 |
Octode
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Re: How would we design electronics to last 100 years?
A characteristic of traditional aluminium electrolytics that I was unaware of until recently is that ESR increases with decreasing temperature. ESR more or less doubles at -10 degrees C when compared to that at 20 degrees C.
This may mean that, at work, we'll need to replace at least some standard electrolytics with polymer types in a system that is to be used at low temperatures. John |
5th Sep 2022, 12:42 pm | #90 |
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Re: How would we design electronics to last 100 years?
Electrolytic capacitor life reduces dramatically with altitude. More pressure difference across seals leading to faster loss of water vapour as the reducing pressure inside promotes faster evaporation.
Solid dielectric electrolytics are better, and then there's big ceramics. David
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5th Sep 2022, 1:43 pm | #91 | |
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Re: How would we design electronics to last 100 years?
Quote:
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5th Sep 2022, 4:13 pm | #92 |
Dekatron
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Re: How would we design electronics to last 100 years?
Yes. If the electrolyte freezes it becomes non-conducting, so all bets are off!
At low temperatures, it becomes more viscous (even plain water is about 3x more viscous at 20 deg C than at 80 deg C). So resistance changes by a corresponding amount. |
5th Sep 2022, 4:49 pm | #93 |
Octode
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Re: How would we design electronics to last 100 years?
Use good quality ceramic capacitors and not the ones as fitted to the Samsung radio in another thread. Shame there was no actual makers name on them.
Also make sure that you have an independant signal source suitable for the equipment being designed, so that the correct signal can also be created in 100 years time. This would mean even more design consideration though. Dave
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10th Sep 2022, 12:49 am | #94 |
Dekatron
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Re: How would we design electronics to last 100 years?
Just use amplitude modulation on a medium wave frequency. It has lasted 100 years already, so might be a good candidate to last another 100 years. Come to think of it, a receiver which only contains a tuned circuit and a diode, can probably also last 100 years so only the transmitter would need some careful engineering.
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