For non flooby dust capacitors the magic is all in process control. You normally need to be making things in the thousands or millions to get the process stable and repeatable.
Ah, do you remember this:
"The capacitor plague was a problem related to a higher-than-expected failure rate of non-solid aluminium electrolytic capacitors, between 1999 and 2007, especially those from some Taiwanese manufacturers, due to faulty electrolyte composition that caused corrosion accompanied by gas generation, often rupturing the case"
A stolen formula for Japaneese capacitor electrolyte was incomplete and made it's way into Chineese capacitors wiith disastoris results.
Electrolyte formula highly guarded.
"The capacitor plague was a problem related to a higher-than-expected failure rate of non-solid aluminium electrolytic capacitors, between 1999 and 2007, especially those from some Taiwanese manufacturers, due to faulty electrolyte composition that caused corrosion accompanied by gas generation, often rupturing the case"
A stolen formula for Japaneese capacitor electrolyte was incomplete and made it's way into Chineese capacitors wiith disastoris results.
Electrolyte formula highly guarded.
And electrolytics in the psu board is such so inconvenience to remove. Most people won’t bother. Those made in china caps must have caused a few hundred tonnes of electrical waste.
The foils you see are quite special. They are processed in various ways to create preferred metal grain structures. They are than etched to create various microscopic surface morphologies. Then electrolyticaly grown oxides are created. After all that, the foils can be put into cans with separators and electrolyte. Then propriety reforming procedures are applied. All of the above will be customised for particular voltages, capacitances, esr, and reliability targets.
You can make a cap, but it will really suck in comparisons to commercial units.
You can make a cap, but it will really suck in comparisons to commercial units.
The original formula used boric acid, water, and glycerin, but things have progressed since the early 20th century with etched foils to increase surface area and proprietary electrolyte formulas for lower ESR and greater resistance to low temperatures. The stolen cap juice that caused all the ruckus a few years ago lacked a preservative, which caused the affected caps to deteriorate and vent prematurely.
The dieletric is a carefully grown film of aluminium oxide nanometres thick on the +ve plate - getting this uniform, stable for decades and low-leakage in aqueous conditions is probably more tricky than you imagine. 🙂
The big question is why? Great electrolytic caps are available for relatively cheap when you consider what goes into them. You’re better off making film caps but even that is not worth the cost of materials and time to get a superior product. Companies have been doing this for a long time and have the details worked out. The old saying about reinventing the wheel applies here.
![DSCN0289[1].JPG](/community/data/attachments/1081/1081171-bead9caff30f074653bc7fec5d5b5f4f.jpg?hash=vq2cr_MPB0)
Alternatively you could say:
"You’re better off making power amplifiers but even that is not worth the cost of materials and time to get a superior product. Companies have been doing this for a long time and have the details worked out. The old saying about reinventing the wheel applies here."
Yes, making film caps is more easy for sure.
Not really - do you have access to equipment for properly metallizing the films without melting them, or in the case of film and foil, equipment for properly handling the foil and insulating film with proper tensioning so that the caps aren't microphonic when you're done with them? Do you have the equipment for properly arc-spraying the end terminations (schoopage - the guy who invented the technique was named Schoop) for non-inductive operation? Good film caps are relatively cheap, just like premium electrolytics. The manufacturers have extensively researched and invested heavily in the techniques of their trade, and have them down down to a routine.
How would you even buy the material, which is only available on wide rolls?
And you would need a precision slitting machine.
And you would need a precision slitting machine.
Bernhard -
Your analogy with power amplifiers is faulty, because at least in the case of power amplifiers, you have access to the properly made parts to get the job done. If you were proposing to make your own transistors/fets, that would be an entirely different story.
Your analogy with power amplifiers is faulty, because at least in the case of power amplifiers, you have access to the properly made parts to get the job done. If you were proposing to make your own transistors/fets, that would be an entirely different story.
If I was to make film caps, I would get sheets of silver foil, silver wire and try stacks instead of rolls.