the effects of throwing electrolytics in backwards

[joem]

so. i made the mistake of throwing in the electrolytics on my first few boards in backwards. stupid me wasnt thinking and i had a handful of 10uf electrolytic caps where the negative was marked with a RED STRIPE... yeah genius on their part, genius on mine. just curious what i couldve damaged. the units were a dod 440, foxx tone machine, ross compressor and an 808. i have since reversed them all and im getting the correct effects out of the units just not sure if its how they should be performing. thanks!

[R.G.]

Electrolytic capacitors conduct in the backwards direction, a little like a diode does. There is some small reverse voltage where they still act like capacitors. For aluminum, it's usually under 1V. For tantalum, it may be a few volts. After that, they conduct current.

If the current is small and doesn't go on very long, they can be reversed back to the proper voltage polarity and still work pretty much OK, especially if you're not using them near their maximum voltage or they're not at hot temperatures, etc.  If the current is bigger and/or goes on too long, the cap becomes first leaky, then shorted.

How much bigger current and how long depends on the cap. Running current through them backwards actually reversed the forming of the oxide film that makes them into capacitors in the first place, so when it eats through, the cap is done for. If you catch it before it goes too far, there is actually some self healing that can happen when you make them the right polarity ... if you catch it before it goes too far.

If you have questions, you have set up a perfect learning experience. Buy yourself another lot of electro caps. They're cheap, maybe  $0.10 each. Listen really well to an effect, then replace them all with new good ones. Now listen again. Did it change?

[hubble]

i was debugging my octavia pedal and switched them for the heck of it to see if MAYBE that was the problem, and i switched them back and it works fine.

[joem]

it looks like im going to have to replace them all. is there a possibility of damaging any near components?

btw how long is very long? 

[sta63bmx]

I didn't know electros were polarized, and I had to copy another guy's charge pump circuit to build an injector driver for my lab.  Good freaking grief.  I suffered for about a week until I finally had someone point it out to me.  That was when I realized that I would have to do any electronics learning on my own, because my college education had been FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS where electronics are concerned. 

I'm still bitter about having to pay $5500 a year to learn pointless crap about Schliemann's mask, the ancient Greeks, music appreciation, political science, and other assorted BS topics when I could have been learning useful electronics and welding skills.  Had to wait until i was a grad student and do that on my own time.  When an "electronics class" talking about basic circuits doesn't ever mention diodes or transistors, you know something is wrong, terribly wrong.

I felt like a moron.  My very first build, a microamp, I flipped on electro, and since they don't hold any voltage, it wouldn't bias up.  Live and learn!  I just flipped mine around and the circuit worked ok. 

[Paul Perry (Frostwave)]

I can't think of any situation where building a pedal wiht electros reversed will damage anything except the electros (yeah, I've had power filter electros explode because they were reversed... but in most parts of a circuit, if the electro is used for coupling, the max posible current flow is too small for any major destruction.)
I'd just yank them out & reverse them.

As for education.... if you want to be a tech, then you have to do a tech course or teach yourself (with help from places like this). Nutrition courses don't have cooking classes. But don't get me onto education

[alderbody]

I'm still bitter about having to pay $5500 a year to learn pointless crap about Schliemann's mask, the ancient Greeks, music appreciation, political science, and other assorted BS topics when I could have been learning useful electronics and welding skills. 

Oooops, man!

Greek member here...  Sorry pal, but ancient Greek stuff is definitely NOT BS!!!

Just don't mix apples with oranges... 

peace

[R.G.]

I'm still bitter about having to pay $5500 a year to learn pointless crap about Schliemann's mask, the ancient Greeks, music appreciation, political science, and other assorted BS topics when I could have been learning useful electronics and welding skills.

I felt the same way when I was in university getting my EE. What culture I was exposed to was compressed into two five-hour courses that surveyed civilization from prehistory to WW2. I got credit for foreign languages for learning FORTRAN (no fooling!). I miss it now. I've had to do a lot of reading to catch up on that useless stuff I missed.

I can't think of any situation where building a pedal wiht electros reversed will damage anything except the electros

Pedals? Probably not. But don't reverse the electros in a solid state power amp.   

[The Tone God]

...FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS FARKING USELESS where electronics are concerned.

Well fark me blind!

I have been noticing that some of the newer "educated" persons seem to be missing some of the basics when I talk to them. It surprises then disappoints me.

Andrew

[stankyfish]

I'm still bitter about having to pay $5500 a year to learn pointless crap about Schliemann's mask, the ancient Greeks, music appreciation, political science, and other assorted BS topics

Jeez, I paid $26,000/year and had to switch majors for a semester just to be ALLOWED to take Political Science and History classes.  I think more college classes should be dedicated to things other than one's major -- it may be the last opportunity you have to learn something different.

And music appreciation is BS?  I don't care if it's aboriginal acoustic folk polka -- if it's music and I get credits, that rules.

[phaeton]

Oh c'mon now you guys.  Here I am musing about getting the motivation and courage to go back to school and chase the EE/CS thing. I'm Even getting encouragement from respected folks on this forum!

And now in this thread you're all talking about quality of modern education and how pointless it all is.





Ok, I'll shaddup now.  Sorry.

[Cliff Schecht]

I'm still bitter about having to pay $5500 a year to learn pointless crap about Schliemann's mask, the ancient Greeks, music appreciation, political science, and other assorted BS topics

Jeez, I paid $26,000/year and had to switch majors for a semester just to be ALLOWED to take Political Science and History classes.  I think more college classes should be dedicated to things other than one's major -- it may be the last opportunity you have to learn something different.

And music appreciation is BS?  I don't care if it's aboriginal acoustic folk polka -- if it's music and I get credits, that rules.

Yeah I'm an EE in school at Texas Tech and I can't stand some of the classes I'm forced to take. @#$%ing high school english, boring history and just plain useless stuff electronics wise. They really make you build some useless shit that doesn't really seem to apply to much of the stuff I learn outside of class. I'm taking summer classes to help get some of the bullshit out of the way but it really is annoying how many extra classes are required.

I have learned quite a bit about electronics though and really am starting to grab a hold of what's going on.

[Dave Eason]

http://en.wikipedia.org/wiki/Electrolytic_capacitor

http://www.faradnet.com/deeley/book_toc.htm

interesting stuff, i remember doing chemistry back in school, and its like a tiny tiny version of the extraction of aluminium essentially!  It would be like reversing that process and not making any alumium, just turning all that you had into oxide rendering the cap useless.

One thing though; if you are passing AC through them, the oxide layer must be reduced then oxidised constantly, so why are they good for DC blocking?  Surely any capacitor can be good for DC blocking?  One friend told me they are often only used just for their larger sizes.

One other thing, in circuits like the deluxe memory man, why put two electrolytics back to back so to speak?  Is this just like making a larger non-polarised cap?  I often see it and don't really understand why it's done, i.e:



I agree about education, my degree never really covers important practical things.  Textbook design is lacking in a lot of practical areas that are important I feel, and often simple things too.  But a lot of the work is definately interesting to me, i.e. the mathematical theory and so on, and all the transforms and signal analysis areas.  It's swings and roundabouts at the end of the day