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Post by Peegoo 🏁 on Feb 7, 2020 19:05:39 GMT -5
Electroboom (Mehdi) is a nut job. Very funny.
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gbfun
Wholenote
I eat cookies to provide you with the best possible experience.
Posts: 463
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Post by gbfun on Feb 7, 2020 19:57:56 GMT -5
Holy Cow again. I sure wish I'd taken electronics classes ! Just not in my schools. Oh well. I'll have to ask the brain trust again. So, after watching this video, what happens if the fluid between the cap plates leaks out ? The caps still work, right ? Assuming the answer is yes, and evidence suggests continued usability, can I assume the caps may short out if the two plates inside contact each other, right ? Assuming I'm right so far, can I assume that the cap will burn out to break the circuit flow like a fuse, rather than send a shock of current through the downstream components ? And even if it does, current in will remain current out...or...the downstream components will already be expecting higher currents following a cap anyway. I guess I'm going to have learn this the hard way, huh ?  |
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Post by Peegoo 🏁 on Feb 7, 2020 23:16:15 GMT -5
As the goo leaks out of an electrolytic cap, the capacitance drifts so far off spec that the circuit will stop working as intended. In guitar amps, filter caps that are drying out make the amp noisy because they are no longer able to filter out the current ripple from the AC power source.
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pdf64
Wholenote
Posts: 556
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Post by pdf64 on Feb 8, 2020 10:16:17 GMT -5
Great video, thanks!
With ‘wet’ type caps, eg electrolytic, the electrolyte goo greatly increases the permitivity between the cap’s plates. If it leaks out, the greatly reduced permitivity means it can’t hold as much charge, hence its capacitance value is greatly reduced. Also its parasitic characteristic of ‘equivalent series resistance’ increases.
Basically, if goo leaks, the cap may as well not be there and as the great ‘goo says, the circuit almost certainly won’t work as it’s supposed to.
Due to the uses ecaps are usually put to in amps, such a fault often won’t cause a fuse to blow.
An exception being the reservoir cap for a fixed bias supply.
The job of the reservoir cap is to fill in the gaps between the rectified pulses of ac (ie act as a reservoir). That actually increases the average Vdc of the supply. If the goo leaks then cap stops filling in the gaps, the Vdc of the bias supply will reduce and the power tubes will run hotter; but probably not draw enough current to blow a fuse. But the power transformer has to deliver the extra current that the power tubes are continuously drawing, and when that gets enough above the rating of the HT winding, the winding will overheat and fail, power transformer ruined!
Because the HT current in that scenario isn’t much above the normal peak loading, it’s very difficult to protect the winding from such a fault with a fuse, even a dedicated HT fuse.
So, good caps in the bias supply are ‘mission critical’!
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Post by Peegoo 🏁 on Feb 8, 2020 11:01:38 GMT -5
That little demonstration tool with the acrylic panels and neo mags is *amazingly ingenious*. It can be used to describe and demonstrate many different principles in physics.
I'm going to make me one!
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Post by LTB on Feb 20, 2020 6:29:35 GMT -5
I wished when I was in college I had him my 1st semester of Basic Electricity. That guy is a hoot!
Reminds me of my first lab on transistor circuits they teamed us in two to do the experiments. Well I got paired with the most brilliant guy in the class. He was hooking up a transistor in a circuit and I told him I think you have it backward. He would not listen and basically poofed me off. Should have seen the expression on his face when he turned the power on and the transistor launched itself from its "Launch pad" and hit the guy right in the forehead. Cool stream of smoke and the Transistor leads remained in the circuit.
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