Capacitors come in many different styles and designs. The terms can be confusing and not to review on the fly. Nor the respective properties. For our needs they can be limited to a few types due to the tension, the design, the availability and the "behaviour". When choosing a capacitor, it is advisable to choose the axial types and small designs with long lead wires. The unit of capacitance is the Farad. But we use only components with a fraction of this value.
1F Farad (F) = 1 000 000 uF microfarads (MFD) = 1000 000 000 nF nF = 1000 000 000 000 pF (MMFD)
The easiest way is to order by capacity.
At the picofaradscale, we use single layer ceramic capacitors or preferably the higher quality mica capacitor called "SilverMica". At the nanofaradscale, there are film capacitors and at the microfaradscale we have electrolytic capacitors which have a polarity.
The picture shows the symbols for capacitors.
Condenser, polarized electrolytic capacitor and bipolar electrolytic capacitor.
The US circuit sign is added at the electrolytic capacitor, because it is frequently used. Even without the + sign.
The labels of the components are handled differently.
The symbol is used from time to time as a comma: Pictured "0,47uF" and "n47", which are 0,47n and 470P.
If no unit is on it, it is pF. But if a comma is on it, there are mostly "uF". So ".1" and "0.1" means 0.1uF. Pictured 33p and 0.1U So 100n.
The number consists of three digits. The first two specify a value in picofarads, the last, the number of zeros. If the last number is a zero in the three-digit indication, it can be read directly. Smaller values are also two-digit. The tolerance can be specified in letters (K is 10%, J = 5%, F = 1%). In the "104" with 100n and a Silvermica (SM) with 500p. The electric strength is usually clear.
When connected in parallel, the capacity of the capacitors sums up.
Formula: Ctotal = C1 + C2 + C3 ....
With series connection of two equal capacitors the capacity cuts in half, the electric strength doubles up.
Formula: 1 / Ctotal = 1 / C1 + 1 / C2 + 1 / C3 ...
Pictured some sacred components. Mallory (now white), Orange Drop, Sozo and Jupiter. Expensive components that have no advantage. I like the axial yellow "Turbular" or similar. The technically best are e.g. the red Xicon Polypropylene.
Capacitors store energy and can easily kill someone. I am always amazed again, what kind of flash even a small capacitor can produce at short circuit. One time, I got a bleeding "hole" in my fingertip, just because I "fished" a loaded 47uF capacitor out of the trash. Anyone who has kids ..... watch out even more.