What is the purpose or function of a capacitor in a circuit?

Question

I am currently enrolled in an automation and control class at a local community college and I would like to know the answer to this question so that I may better understand the material.

Thank you in advance for any answers.

Answer 1

A capacitor is a simple component that can be put to different uses.

1) A capacitor can be used in a peak detector circuit. For example in a simple power supply diodes are used to convert ac to dc but the dc will have a lot of ripple. A capacitor is added to keep the voltage near the peak value. Peak detectors are also used in AM receivers.

2) A capacitor can be used in a filter that will allow some frequencies to pass but will block other frequencies.

3) a capacitor can be used to ac couple stages of an amplifier (and block dc).

4) a capacitor can be used in a "tuned circuit".

Answer 2

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 3

It depends on the circuit. Here are some examples of what a capacitor can do.

1. Block DC and pass AC
2. Filter out noise -- again, by passing alternating current noise, while keeping the direct current intact.
3. Correct for an inductive power factor on power transmission lines.
4. Store energy (like the answerer above, says). In this case it may be used in place of a battery for back-up power.

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Answer 4

If you have a fairly low energy circuit and need high output for one of the tasks a capacitor is used. An example of this would be in the flash of a camera. Most camera's run on a low voltage a fairly low current but powering the flash for that split second takes a lot of energy. That energy is stored in a capacitor. This is also the reason you have to wait for the flash to "charge", you're actually waiting for the capacitor.

Answer 5

Basicaly,a capacitor was made to store the energy in electostatic form(charge store on plates).its use marely depends upon the circuit.it stores the energy and when it is allowed a path it discharges itself.

Answer 6

Capacitors are used to store energy.

Answer 7

that is many purpose of a capacitor.capacitor can store certain voltage and it can smoothen the signal.