Capacitors
Capacitors are part of the basic building blocks of electronics and need to be mastered before progression with electronics. Did you know, in the olden (classical) days of electronics, capacitors used to be known as condensors!
How They Are Made
A capacitor is made up of two conductors near each other (close, but not touching). If greater capacitance is needed, then larger areas, and closer spacing is required. Usually, a thin conductor plate has has insulating material on it (known as a dielectric).
Their Properties
Capacitors exhibit the property Q = CV. That is, a capacitor or C farads with V volts across it has Q coulombs of stored charge displaced.
Capacitors may appear to be frequency-dependent resistors because, for example, they allow you to create frequency-dependent voltage dividers, but they are far more! For some applications (coupling and bypass), you don't really need to know much more, but for larger applications (energy storage, resonant circuits and filtering), you need to know more.
Capacitors cannot dissipate power, despite current being able to flow through them, as the current and voltage are 90° out of phase. The current is not proportional to the voltage, but instead to the rate of change of voltage. If you change the voltage across a farad by 1 volt per second, you are supplying an amp.
Capacitors in Parallel and Series
The total capacitance of capacitors in parallel is the sum of their individual capacitances: C(total) = C1 + C2 + C3 + C4 + ....
For capacitors in series, the formula is reminiscent of the formula for resistors in parallel: C(total) = 1 ÷ ((1 ÷ C1) + (1 ÷ C2) + (1 ÷ C3) +(1 ÷ C4) + ...)