Capacitors – Erica Synths EDU DIY Wavefolder Eurorack Module Kit User Manual
Page 31
CAPACITORS
A capacitor is a bit like a balloon that you can attach to the open end of a pipe
. If
there’s some pressure in the pipe, the balloon will fill up with water until the pressure
equalizes. (Since the balloon needs some space to expand into, both of the capacitor’s
legs need to be connected to points in your circuit.)
Then, should the pressure in the pipe drop, the balloon
releases the water it stored into the pipe. The maximum
size of the balloon is determined by the capacitor’s
capacitance, which we measure in farad (F). There are
quite a few di
ff
erent types of capacitors: electrolytic,
foil, ceramic, tantalum etc. They all have their unique
properties and ideal usage scenarios – but the most
important distinction is if they are polarized or not.
You shouldn’t use polarized capacitors against their polarization (applying a negative
voltage to their positive terminal and vice versa) –
so they’re out for most audio-related
uses like AC coupling, high- & low-pass filters etc.
Unlike resistors, capacitors have their capacitance value printed onto their casing,
sometimes together with a maximum operating voltage.
Be extra careful here!
That
voltage rating is important. Your capacitors can actually explode if you exceed it! So they
should be able to withstand the maximum voltage used in your circuit. If they’re rated
higher –
even better, since it will increase their lifespan. No worries though: the capacitors
in this kit are carefully chosen to work properly in this circuit.
Ceramic capacitors usually come in disk- or pillow-like
cases, are non-polarized and typically encode their
capacitance value. Annoyingly, they rarely indicate
their voltage rating –
so you’ll have to note it down
when buying them.
Film capacitors come in rectangular, boxy cases, are
non-polarized and sometimes, but not always, directly
indicate their capacitance value and their voltage rating
without any form of encoding.
Electrolytic capacitors can be identified by their cylinder
shape and silver top, and they usually directly indicate
their capacitance value and their voltage rating. They
are polarized – so make sure you put them into your
circuit in the correct orientation.
For a detailed breakdown, look up There are also calculation
tools available.
If yours do encode their values, same idea applies here –
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