Calculating the capacitance of caps in series or parallel is a very simple operation.Can a useful capacitor bank be built either parallel or series, using a variety of electrolytic capacitors that differ in both voltage and capacitance? Is there is an online calculator that will calculate this?
The key to his question lies in the part in which he asks "using a variety of electrolytic capacitors that differ in both voltage and capacitance?" ... that is not so easy to find by just googling it... it takes a basic amount of experience to answer that, I thinkCalculating capacitors in serial or parallel is essentially the same as resistors except in reverse.
But I find it EXTREMELY hard to believe you were not able to find the answer online. All you had to do was look at the top of this forum, as well as several hundred if not thousand of other places on the internet.
http://www.allaboutcircuits.com/textbook/direct-current/chpt-13/series-and-parallel-capacitors/
You just didn't look.
The key to his question lies in the part in which he asks "using a variety of electrolytic capacitors that differ in both voltage and capacitance?" ... that is not so easy to find by just googling it... it takes a basic amount of experience to answer that, I think
Not in the case of caps in series .... caps normally are manufactured with a huge tolerance compared to other components, such as resistors. A tolerance rating for a cap can be as high as 20%, and that would affect their charge/discharge rate, which can have a significant effect in the voltage between them when cycling.OK I will give it to the OP then. Capacitors in parallel is fairly straight forward as far as voltage rating. But I am guessing either way you would want the same rating.
And also have very little regard for money and finances, the way you've described things...you better do the math or wear a full face shield, a leather apron, and dragon hide gauntlets up to your shoulders.
Calculating the capacitance of caps in series or parallel is a very simple operation.
If in parallel, just add their capacitance.
If in in series, total capacitance is given by the equation 1/Ct = 1/C1 + 1/C2 + .... + 1/Cn, in which n is the total number of capacitors.
If you use them in parallel, keep in mind that the cap that has the lowest voltage rating will be the first to blow if that voltage is exceeded. And, it is usually NOT recommended (though it can be done safely, if you know what you're doing) that you use capacitors in series, because voltage between them can vary significantly during charge/discharge cycles, mainly because different caps can have different properties, such as their rate of charge.
Calculating capacitors in serial or parallel is essentially the same as resistors except in reverse.
But I find it EXTREMELY hard to believe you were not able to find the answer online. All you had to do was look at the top of this forum, as well as several hundred if not thousand of other places on the internet.
http://www.allaboutcircuits.com/textbook/direct-current/chpt-13/series-and-parallel-capacitors/
You just didn't look.
Thank you for your prediction / opinion, I will keep it in mind.And also have very little regard for money and finances, the way you've described things...
and thanks!, btw
I do follow you calculations and I gather there is no simple formula to solve the mixing and matching of capacitors. I can get the properly matched ones, I was hoping to make use of a lot of varied capacitors in possibly some sort of voltage booster. Thank you for your answer and explaining with math the complexity of the problem.I don't remember someplace to point to, but I can do the job.
4 example: 2 capacitors in series, both rated at 10 uf, 250 V and you want to hit them with 450 VDC.
(This is an old problem from the Fender guitar amplifiers.)
Theoretically, you have 5 uf at 500 volts.
In reality, if one capacitor is 20% over its labeled size and the other is 20% below its labeled size, you have an 8 uf in series with a 12 uf.
Pick a frequency, any frequency, and you will see that the impedance of each capacitor is the inverse of its capacitance. The 8 uf resembles 12.5 ohms and the 12 uf resembles 8 and 1/3 ohm. Now we're in a basic Ohm's Law situation. The voltage is distributed in a 60/40 proportion. Flip the standby switch to, "on" and the 8.333 ohm resistor charges to 180 volts in a quick pulse. The 12.5 ohm resistor charges to [450V x (12.5/20.83)] and that is 270 volts. Bang. It's outside its voltage rating.
This is the kind of worst case calculation you have to do.
I've seen ratings as bad as +80%/-20%. If you want to play mix&match with that kind of sloppy tolerances, you better do the math or wear a full face shield, a leather apron, and dragon hide gauntlets up to your shoulders.
The key to his question lies in the part in which he asks "using a variety of electrolytic capacitors that differ in both voltage and capacitance?" ... that is not so easy to find by just googling it... it takes a basic amount of experience to answer that, I think
I couldn't find either, thank you.Not in the case of caps in series .... caps normally are manufactured with a huge tolerance compared to other components, such as resistors. A tolerance rating for a cap can be as high as 20%, and that would affect their charge/discharge rate, which can have a significant effect in the voltage between them when cycling.
Somewhere in this place there's a more detailed explanation as to why that happens, but I can't seem to find it... @#12, can you help me out here? I have a feeling you can point us in the right direction.
When people are free to pursue goals unfettered by presumed limitations on what they can accomplish, they just may manage some extraordinary feats through the combined application of native talent and hard work.And also have very little regard for money and finances, the way you've described things...
and thanks!, btw
Thank you, but that quote is not originally mine. I found it in this place, and liked it so much that I decided to use it as my signature here.When people are free to pursue goals unfettered by presumed limitations on what they can accomplish, they just may manage some extraordinary feats through the combined application of native talent and hard work.
That is a great quote and it is exactly the way some things have to be approached, I would add, the building on the knowledge already discovered through the past research and experience both gained by oneself and from others.
Now you've got me thinking about the difference between impedance and reactance... I'll more carefully study this page, and then get back here if I have further questions.Pick a frequency, any frequency, and you will see that the impedance of each capacitor is the inverse of its capacitance.
Don't fry your brain over it. I am famous for not being precise all the time. Witness the, "Gold Standard" for blood pressure. A million physicians have believed it for over 100 years, but WBahn thinks they used the wrong word.impedance and reactance... I'll more carefully study this page,
Thread starter | Similar threads | Forum | Replies | Date |
---|---|---|---|---|
Simple question about capacitor | Analog & Mixed-Signal Design | 12 | ||
C | Simple capacitor question | Homework Help | 7 | |
L | Need Help! Simple capacitor question..maybe | Analog & Mixed-Signal Design | 6 | |
A | Mcu output to capacitor (simple question :)) | Analog & Mixed-Signal Design | 12 | |
S | simple capacitor question | Homework Help | 3 |
by Luke James
by Jake Hertz
by Luke James