What are Capacitors and why are they used in electronic circuits?

Question

I'd understand that capacitors are used to store charges, but why are they used??? why they have to be in electron circutis?

Answer 1

they are used when you want to use a lower voltage

Answer 2

Capacitors are devices used to store an eletric charge. To understand capacitors you must understand charge but that's a whole other chapter. A capacitor usually consists of two metal plates separted by an insulator which is called a dieletric(wax or varnish can be used). Capacitors can be used to tune a radio by turning the knob you change the common area between the plates. The flash on a camera uses a capacitor to store charge and release the charge very quickly to give an intense light. If you look at a capacitor in an electric circuit board it is a small cylinder object but it is basically two metal plates with a dieletric between.

Answer 3

At the heart of understanding the function of a capacitor is understanding the voltage across a capacitor is ideally the time integral of the current into the capacitor divided by its capacity. Capacitors are useful in realizing linear circuits such as power supply filters (storing energy by integrating the half sine wave of the rectified mains and releasing it later), resonant circuits of oscillators (integrating the current formed by the collapsing magnetic field from an inductor to increase the voltage across the capacitor and then returning that energy to the inductor cyclicly). In both examples here I'm sure you've noted that the capacitor is an energy storage element. The form of the stored energy is charge. Storing energy in this form has multiple uses. Charge coupled devices (CCD) store information in the form of charges on capacitors as a form of analog memory. Coupled with photo diodes they become sensors for many digital cameras. Within a field effect transistor, the capacitor becomes the channel enhancing or depleting element.

Answer 4

Capacitors pass alternating current but block direct current, so they are useful at passing ac signals from one circuit to another, even though there is a different dc potential.

They are also useful in smoothing out dc supplies, because they pass any ac ripple to ground leaving the dc alone. In this way supplies with a high ac component (ripple) are smoothed out.

They can also hold a charge. This is used in electronic flash guns. The oscillator charges the capacitor (hence the whistle) and when you press the shutter, the charge is connected to the flash tube, which duly does it's business.

Answer 5

one use of capacitors in a electronic ciruit is in a rectifier:
a rectifier turns AC voltage into DC voltage, the AC voltage starts as a wave and is passed through a diode bridge to produce a choppy DC voltage (the wave is cut in the middle and the low parts are put in line with the high parts), capacitors smooth out the peaks of the waves to produce a much straighter line.

Capacitors are also used in Power electrics to counteract the effect of inductive resistance. (electro magnets of any nature cause the power to move out of phase (basically dragging the AC waveform out of the right timing)) and capacitors move the power the opposite direction also out of phase ( but capacitors can be used to offset the inductors, making the waveform closer to what it should be)

Answer 6

Caps can be used to store an electrical charge, they can be used to smooth out voltages, they can be used as filters in conjunction with coils (inductors) and resistors, in audio circuits, RF circuits, power circuits, and so on and so on and so on .... a wide topic and not really for the faint hearted.

The ones that store a charge hurt like hell if you act as a shorting link across the two contacts!!

Answer 7

It depends in which circuits they are used. They are used in AC circuits as filters. AC current flows through a capacitor but depending on the size certain frequencies can be filtered out.

In conjunction with coils they can be used to create an occillating circuit.

Answer 8

they store electrical charges with two metal plates that vary by how far apart they are (no wonder some capacitors are huge) and they will discharge when you stop charging as in when you take the charge off of them they are alot easier to understand then inductors theirs capacitance is measured in farads and their charge is measured in coulombs

c=q/v
v=q/c
q=c*v
where
c=farads(exact value most capacitors are micro farads you'll have to learn how to translate it to farads theres a list that may help you at wikipedia the link is in the sources)

q=coulombs

v=volts

Answer 9

Capicators are like battieries but will realease its charge all at once instead of slowly like battiries so there is no voltage drop on a curcuit.

Answer 10

they store the electric and let it out smoothly so as not to damage the components which are in line with it (as electric some times surges and can give the componet eratic voltage)

Answer 11

capacators are tiny chips that when a current electricaty
is past through it the copacators charge the capacators like a rechargable battery and when the electrick currnt stops (240 volt mains) the capacators will keep it going 4 a while like chaging from 240 volt mains too battery