A one-hundred nano-Farad capacitor is written as 100nF or just 100n. It may be marked as 0.1 (meaning 0.1uF which is 100nF). Or it may be marked with 104, meaning 10 and four zeros: 100000pF which is equal to 100nF. A twenty-two pico-Farad capacitor is written as 22pF or 22p Capacitors have a voltage rating, e.g. 16V, 50V.
A: Capacitor code values are used to represent the capacitance value of a capacitor component. Capacitors are electronic components that store and release electrical energy. The code values help in identifying the capacitance value of a capacitor without having to write the full value in Farads. Q: How are capacitor code values expressed?
The image above is of an electrolytic capacitor marked with “100μF,” meaning it has a capacitance of 100 microfarads (the μ prefix indicates 10 −6). Expressed differently, this is 0.0001 farads. While this might seem like an extremely tiny number, it’s actually fairly typical, as a full farad is quite large in practical terms.
The voltage rating is the maximum voltage that a capacitor is meant to be exposed to and can store. Some say a good engineering practice is to choose a capacitor that has double the voltage rating than the power supply voltage you will use to charge it.
Remember that capacitors are storage devices. The main thing you need to know about capacitors is that they store X charge at X voltage; meaning, they hold a certain size charge (1µF, 100µF, 1000µF, etc.) at a certain voltage (10V, 25V, 50V, etc.). So when choosing a capacitor you just need to know what size charge you want and at which voltage.
For the capacitor to charge up to the desired voltage, the circuit designer must design the circuit specificially for the capacitor to charge up to that voltage. A capacitor may have a 50-volt rating but it will not charge up to 50 volts unless it is fed 50 volts from a DC power source.