AC Capacitor vs DC Capacitor
AC capacitor and DC capacitor, to know the difference between these capacitors we first need to know what capacitor is. It is basically an electronic device that is made up of two conducting plates separated by an insulating medium. The value of a capacitor depends upon the surface area of the plates and the distance between the plates (which is dependent upon the thickness of the insulating plate). Capacitance or the value of a capacitor is referred in terms of microfarads which is a millionth of a farad. Capacitor was invented by German scientist Ewald Georg in 1745. He took a glass jar, filled it partly with water, and plugged the jar with a cork that had a wire running through it. The wire dipped in water and when it was connected with a source of static electricity it caused the jar to become charged.
In a practical way, a capacitor can be considered as a battery. But where a battery produces electrons on one terminal and absorbs them on other terminal, capacitors only store electrons. It is easy to make a capacitor with two pieces of aluminum foil separating them with a piece of paper. Capacitors are made use of heavily in appliances and gadgets such as radio circuits, clocks, alarms, TV’s, computers, X-ray and MRI machines and many more machines that are electronically operated.
Major difference between AC Capacitor and DC Capacitor
If a capacitor is attached to a battery, once the capacitor is charged, it allows no current to flow between the poles of the battery. Thus it blocks DC current. But in case of AC, the current flows through the capacitor uninterrupted. This is because the capacitor is charged and discharged as fast as the frequency of the current. Thus a capacitor allows the current to flow continuously if it is AC.
Capacitor and DC
When a capacitor is connected to a DC source, initially the current increases but as soon as the voltage across the terminals of the capacitor equals the applied voltage, the current flow stops. When current stops flowing from the power source to the capacitor, it is said to have been charged. Now if the DC power source is withdrawn, the capacitor will retain a voltage across its terminals and remain charged. To discharge the capacitor, touching the external leads together is enough. It is prudent to remember that capacitor cannot take place of a battery and only serves to fill very small dips in voltage.
Capacitor and AC
In case of an AC source applied to a capacitor, current flows only as long as power source is on and connected.