hi, im a student leaning about electronics and after reading the internet and looking on online shops that sell capacitors im so confused.
ceramic, polystyrene and electrolytic typical tolerance, typical capacitance range, typical voltage and typical applications. i know typical can be a great range and thats where the confusion is coming from as one website says one thing and then another will say another.

so far i have
ceramic as 1pf-0.1uf, +-5%, 2v-24v, audio to radio frequency
polystyrene as 10pf-47nf, +-10%, 30-630v storage applications
electrolytic as 1uf-47000uf, +-50%, 50v, power supply

am i in the correct ball park or is there somebody that knows more than myself that can correct me

 

i have just found another website saying this about
ceramic as 10pf-100uf, +-5%, 16v-15kv, audio to radio frequency

 

Welcome to AAC!

In general your list is correct, and it is good enough for you at this point in learning. If you want more information, instead of browsing websites with such summaries, look at the sites of part suppliers like Mouser or Arrow to see what is actually for sale.

The best way to refine your understanding of this is to study practical circuits and see which parts are specified for them. You will come to a clearer understanding of this over time as you do.

Don’t fret it, when you need to choose a type, you can ask here. When you analyze and/or repair something, you will see what is actually used.

Good luck!

 

Thankyou for the reply. I didn’t even know about those websites. I’ve just been buying everything from eBay.

To decouple dc from ac in a 5v amplifier would I be correct in saying to use a small ceramic for the high frequencies and a electrolytic for the storage?

 

Thankyou for the reply. I didn’t even know about those websites. I’ve just been buying everything from eBay.

To decouple dc from ac in a 5v amplifier would I be correct in saying to use a small ceramic for the high frequencies and a electrolytic for the storage?

Coupling capacitors are chosen for their voltagesand frequency response. A ceramic would certainly handle the voltage, and audio frequencies.

Could you be more clear about "storage"?

 

I was thinking if the voltages dipped to much that the main line had already dipped then the bigger electrolytic would be there in reserve. Plus it would filter the low frequencies or am I going off the path

 

I was thinking if the voltages dipped to much that the main line had already dipped then the bigger electrolytic would be there in reserve. Plus it would filter the low frequencies or am I going off the path

Electrolytic capacitors are used in power supply filter circuits, in conjunction with an inductor, to remove ripple. While it is something like "storage", it's not that. Some capacitors, in particular "super caps" are used for actual storage.

 

So I would use a electrolytic capacitor to smooth out the ripple of a 30v power supply and a ceramic to decouple dc from ac in a 5v signal amplifier circuit?

I think I’m starting to understand!

 

hi,
Look thru this pdf.
E

 

Wicked read.
Not too complicated
Gives a general rule to someone learning. Thanks for that

 

Your approach is pigeonholing a given type of capacitor for a given application.

As that pdf indicates there are many types of materials used for capacitor construction, air, paper, ceramic, mica, mylar, plastic (poly---), aluminium, tantalum.

There are also polarized and non-polarize capacitor.

Another perspective (and a better one) is to look at the specific circuit application of a capacitor and then ask what would be the preferred type of capacitor to use in that application. In order to gain some insight and experience in choosing capacitors, look at reliable project descriptions and see what types of capacitors are recommended for that specific place in the project.

 

The PDF doesn’t have a publication date, but it appears a little dated and does not include SMT/SMD capacitors. I looked for a capacitor reference that includes SMT/SMD. The link is to one such reference that’s not as good as the pdf. But it is an introduction. You may be able to find a better one yourself.

 

hi, im a student leaning about electronics and after reading the internet and looking on online shops that sell capacitors im so confused.
ceramic, polystyrene and electrolytic typical tolerance, typical capacitance range, typical voltage and typical applications. i know typical can be a great range and thats where the confusion is coming from as one website says one thing and then another will say another.

so far i have
ceramic as 1pf-0.1uf, +-5%, 2v-24v, audio to radio frequency
polystyrene as 10pf-47nf, +-10%, 30-630v storage applications
electrolytic as 1uf-47000uf, +-50%, 50v, power supply

am i in the correct ball park or is there somebody that knows more than myself that can correct me

The type of capacitor (ie, what it's made of/how it's made) is chosen usually by understanding why a capacitor is made the way it is, it's pros, and it's cons. For example, electrolytic caps have an electrolyte (think liquid or liquid coating) in them for the dialectric. While their method of manufacture makes them cheap to make- hence why they are everywhere, they will also fail after some period of time (could be years) as they will dry out. But they are usually very inexpensive. Note that some caps are polarized, while others are not. Some caps are designed to handle higher voltages and currents than others, or respond faster than others.

The factors in choosing a a type and rating of cap usually are:
dimensions
electrolyte/manufacture
purpose/circuit requirements
cost

Not necessarily in that order.

 

Thankyou all for your time and information today. I think the best I’m going to learn is to make mistakes and blow some things up. I just wanted a very general typical idea of what capacitor might be used for general things and there tolerance and voltage range. I now understand that any capacitor can be used for any kind of circuit. More some than others for a variety of reasons.

No body has disagreed with my general idea so I think I’m on the right track for a beginner. Didn’t even know capacitors existed until last week

 

hi D47,
Polarised capacitors will not tolerate reversed voltage connections.
Especially Tantalum which will explode into a mini fireball of metal, so always ensure that Tant's are correctly connected and voltage rated.
E

 

Here's another perspective. Capacitance and voltage rating both add to the cost, as does the tightness of the tolerance rating. (There are other measures, also, such as temperature.) In general you want to choose the cheapest capacitor that will do the job. So you choose a tolerance and voltage level that are "good enough" for the application. Sometimes it's prudent to spend a fraction more to buy yourself extra insurance, ie. a tighter tolerance or a higher voltage rating, etc.

If you need more than about 1µF, the electrolytic capacitor is the cheapest option. Look it up: A 5µF ceramic is not cheap compared to a comparable electrolytic! Electrolytics have a number of other shortcomings and probably wouldn't exist if they weren't so dramatically cheaper at high capacitance levels.

 

 

Another question.
Earlier I mentioned what capacitor for decoupling dc from ac in a amplifier circuit. I mentioned a ceramic and a electrolytic. Am I correct in thinking I need the ceramic for the local decoupling and the electrolytic for the bulk decoupling

 

A ceramic capacitor should not be used to couple or filter audio because it is microphonic (a bump or vibration causes it to produce an interfering signal) and it causes low frequency distortion as its value changes from the signal voltage across it.