why does a capacitor is always designed for very low values like nano or pico Farad?

Answer 1

A capacitor has a capacitance of one farad when one coulomb of charge is stored due to one volt applied potential difference across the plates. Since the farad is a very large unit, values of capacitors are usually expressed in microfarads (µF), nanofarads (nF), or picofarads (pF).

Answer 2

A capacitor is a device that stores electrons. The basic capacitor is made up of two conductors seperated by an insulator, or dielectric. Depending on how the capacitor is built, the dielectric can be made of paper, plastic, mica, ceramic, glass, a vacume or any other such non conductive material. Capacitor electron storing ability (it's capacitance) is measured in Farads. One Farad is actually a huge number of electrons (6,280,000,000,000,000,000 electrons to be exact), so we usually rate capacitors in microfarads (uF) and picofarads (pF). One uF is equal to 0.000,001F and one pF is equal to 0.000,000,000,001F. A non polar capacitor is a type of capacitor that can be connected any way in a circuit. In other words, there is no positive or negative. Common types of non polar capacitors are ceramic, mica and some electrolytics.

hey earth being largest capacitor has only a capacitance of 0.0007 Farad ,then u will understand what a small capacitor has

Answer 3

A capacitor has a capacitance of one farad when one coulomb of charge is stored due to one volt applied potential difference across the plates. Since a farad is a very large value values for capacitors are typically expressed as micro- or pico-.

Answer 4

In all practical circuits there are a range parameters that work together

Current can be measured over many decades
pico, nano, micro, milli and Amps

Voltage from micro to Kilo

The smallest capacitance that is realistic to measure
is 1pF

The biggest manufactured is 1F (these replace batteries in memory backup applications) size is typ 15mm dia x 5 mm deep

So I disagree that capacitors are nano or pico

I can now get 2.2 uF capacitors in SMD 1206 size

Electrolytics have managed milli Farads for years
Eg 20,000uF = 2 milli F

Answer 5

It is easier and cheaper to make a capacitor with low capacitance since less material is needed in it.

Capacitors are chosen because their values match what a circuit needs. Those used with higher frequency circuits (like radios) tend to be very small since they have very low impedance at those frequencies. Those used for filtering noise (AC hum from DC power supplies) tend to be larger values since they are bypassing 60 or 120 cycles and that requires lots of capacitance to reduce the impedance..