#10 - Capacitors Intro

What’s a Capacitor?

The technical Wikipedia definition of a capacitor is “a passive two-terminal electrical component used to store energy in an electric field”. A simple translation of that is a storage tank. If you put a voltage across it a capacitor will store your voltage even after you’ve removed the voltage source. As it turns out this behavior can be used in a lot of applications but we’ll mainly be using it to smooth out power supplies in our projects.

The Important Numbers

For our basic needs we really only need to know 3 stats on our capacitors

Voltage RatingThe maximum working voltage that you can apply to the capacitor. Do not exceed this. It’s best to give yourself some room and not push it to the limit.
CapacitanceThe storage capacity of the capacitor.
PolarityIf polarized a capacitor will have some marking or symbol to indicate which lead is which. Always refer to the datasheet.

Bonus Stat

One additional stat that is important to know for more advanced applications is the type of capacitor. There are many different types of dielectric materials that can be used in capacitors and each have their strengths and weaknesses. This makes certain kinds of capacitors better for certain applications than others. When that’s important to know we’ll be sure to point it out but for this introduction just be aware that there are different types of capacitors.

To discharge smaller capacitors you can place a screwdriver shaft across the leads. Make sure the handle is insulated and only do this with smaller capacitors as larger capacitors with higher voltages can melt your screwdriver.


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