Capacitor Purpose in everyday electronics

Hi,

I know what capacitors are in general but I can't understand the purpose of capacitors in general.
I understands its purpose in flash camera where a high voltage is required at a click of a button. But I have seen capacitors in every possible electronic device.

Please can anybody explain the general purpose of a capacitor with examples of daily home devices other than camera.

I will really appreciate any help.

Thank You

rockelectro said:

I know what capacitors are in general but I can't understand the purpose of capacitors in general.

Click to expand...

In electronics, the two most important properties of a capacitor are
*the ability to block dc current (steady state condition after transients have disappeared) and to let path ac current,, and
*to produce a phase shift of 90 deg between ac current and ac voltage (across the cap).

The first property is exploited to separate dc and ac signals and the 2nd property can be used to create filter and oscillator circuits.

rockelectro said:

Hi,

I know what capacitors are in general but I can't understand the purpose of capacitors in general.
I understands its purpose in flash camera where a high voltage is required at a click of a button. But I have seen capacitors in every possible electronic device.

Please can anybody explain the general purpose of a capacitor with examples of daily home devices other than camera.

I will really appreciate any help.

Thank You

Click to expand...

Hello

Basically, a capacitor is a device that stores "energy", is like a battery that charges and discharges very quickly. You see them in every electronic circuit for this reason. For example, in a digital circuit, they provide a quick and fast source of energy to the ICs on a digital board because they "release" the stored charge when the IC switches its outputs, it's like having one little battery for each IC, that's why you see a bunch of them in a digital board.

In Analog boards they are used commonly as filters, (altough they are used as little bateries here as well), because the capacitors have the property of "blocking" the DC current, in other words, the higher the frequency, the lower the resistance they present to the current flow, so, when combined with resistors you can make filters for different frequencies.

Then, basically, they are used as little batteries to provide fast and quick power, they are used as "AC Resistors" whose resistance value varies with the frequency and as such, they are used to filter out noise.

Of course there is a lot of theory behind this, but I hope this helps you at least to understand a little more why you see lots of then in all electronics and what are they used for generally speaking.

Regards

rockelectro said:

Hi,

I know what capacitors are in general but I can't understand the purpose of capacitors in general.
I understands its purpose in flash camera where a high voltage is required at a click of a button. But I have seen capacitors in every possible electronic device.

Please can anybody explain the general purpose of a capacitor with examples of daily home devices other than camera.

I will really appreciate any help.

Thank You

Click to expand...

A capacitor is an energy storage device that is unlike a battery. Both components store electrical energy, but a capacitor stores its energy in an electostatic field residing in its dielectric insulator. A battery stores in energy in a reactive chemical mixture. A cap can be energized and deenergized many times. Only special batteries can be energized and deenergized, and then only under special circumstances. With the exception of an electrolytic cap, a cap can be energized in reverse. A battery cannot be energized in reverse. A cap will resonate with an inductance, but a battery will not. A cap can be energized to any value of voltage below is max rating, but a battery can be only be held to a narrow range of voltage without damage. That means a cap can be shorted, but a battery cannot.

The resonance of a cap and a inductance is used to tune your receiver to a particular station. It is used to help start some of the motors in your home appliances. It is used in timing circuits around your house. A little searching on your part can find a myriad of uses for caps.

Ratch