Hardware Hacking Projects for Geeks

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Introduction

Ceramic

A ceramic capacitor has the simplest design structure, consisting of two

metal plates with a chemical coating between them. A ceramic material

coats and protects the metal plates.

Ceramic capacitors can be used for a variety of applications. They are typi-

cally very stable over a wide temperature range, have a tight tolerance, and

retain their capacitance over a wide frequency range. They are available in

values from a few pico-Farads up to a few micro-Farads.

Ceramic capacitors are non-polarized; they can be placed in a circuit with-

out concern for which terminal is connected to the positive signal. They

also have very low leakage; once charged, they will hold that charge for a

relatively long period of time.

Tantalum

Making this type of capacitor involves placing a tiny pellet of tantalum,

a rare element, on a wire, growing an MnO2 layer, and attaching another

wire. The package is covered in plastic or ceramics. The tantalum element

can store a large amount of charge in a small space.

This type of capacitor exhibits low leakage current, a small size for rela-

tively large capacitance, and good temperature stability. However, it has a

low operating voltage (50 volts maximum depending on the part), and it is

polarized. If the plus side is connected to a negative voltage, the capacitor

will likely be permanently ...