Capacitor & Pith Ball: Exploring Charge Transfer & Static Electricity

In summary: However, with the aid of a voltmeter and some materials like a plastic comb, a discharged capacitor can be made to generate a modest amount of electricity. This is not a generator as such, but can be useful in demonstrating the principles of static electricity.
  • #1
deval vyas
8
0
Suppose I first charge a capacitor so that one plate is positively charged and another negatively. Now I remove the charging source and ground only one of the terminals say negative terminal, will there be a net positive charge in the capacitor that can be detected by a pith ball?
Can a capacitor be used as static electricity generator?
 
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  • #2
deval vyas said:
Suppose I first charge a capacitor so that one plate is positively charged and another negatively. Now I remove the charging source and ground only one of the terminals say negative terminal, will there be a net positive charge in the capacitor that can be detected by a pith ball?
Can a capacitor be used as static electricity generator?
Grounding one of the terminals will have no effect on the charge on the plates, because with the other terminal connected nowhere, charge is unable to enter or leave the capacitor.

A charged capacitor is a static source of electricity, but not a generator.
 
  • #3
Thanks...So if charged capacitor is source of static electricity, can it move the pith ball or attract small bits of paper like a charged balloon or charged comb does? is it possible to build a electrostatic levitator based on parallel plate capacitor?
 
  • #4
It's the voltage that is relevant to attracting pieces of paper. In principle, the voltage from a charged capacitor could be used, in place of a charged plastic comb; in practice you won't be able to easily demonstrate this at home because of the high voltage needed, probably a few thousand volts, at least. It is dangerous to try to produce and store voltages of that magnitude, except by techniques such as involving friction on a plastic comb.

It is easy to overlook the high voltages associated with static electricity we experience daily around us. On dry winter's nights my fingertip can discharge a spark over a 0.5 cm air gap when reaching for canned items on the supermarket shelf!
 

FAQ: Capacitor & Pith Ball: Exploring Charge Transfer & Static Electricity

What is a capacitor and how does it work?

A capacitor is an electronic component that stores electrical charge. It works by having two conductive plates separated by an insulating material, known as a dielectric. When a voltage is applied to the capacitor, one plate becomes positively charged and the other becomes negatively charged. This creates an electric field between the plates, allowing the capacitor to store charge.

How does static electricity differ from current electricity?

Static electricity is a buildup of electric charge on the surface of an object, while current electricity is the flow of electric charge through a conductor. Static electricity is usually created by friction or contact between two insulators, whereas current electricity is typically generated by batteries or power plants.

What is the relationship between capacitance and charge?

Capacitance is a measure of how much charge a capacitor can store. It is directly proportional to the amount of charge stored on the capacitor, meaning that as the charge increases, so does the capacitance. This relationship is described by the equation C = Q/V, where C is capacitance, Q is charge, and V is voltage.

How does a pith ball electroscope work?

A pith ball electroscope is a simple device used to detect the presence of static electricity. It consists of a small, lightweight ball made of a non-conductive material, such as pith or polystyrene, suspended by a thread. When a charged object is brought near the pith ball, it will be attracted to the ball and may cause it to move or stand up straight. This is because the charged object creates an electric field that polarizes the atoms in the pith ball, causing it to become temporarily charged and attracted to the opposite charge of the object.

How is charge transferred in a capacitor?

Charge can be transferred into a capacitor by connecting one plate to a power source, such as a battery, while the other plate is connected to ground. This causes the capacitor to charge up, as charge is transferred from the power source to one plate, through the dielectric, and onto the other plate. The capacitor will continue to charge until the voltage across it is equal to the source voltage, at which point the flow of charge will stop. Charge can also be transferred out of a capacitor by connecting the two plates together, allowing the stored charge to flow back into the power source.

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