Capacitance Flashcards
What is capacitance?
The ratio of charge to voltage on a device
What is a capacitor?
A device capable of storing an electrical charge.
What can capacitors be used for?
- Volatile memory storage when power supplies are interrupted
- Pulsed weapon systems requiring high voltage discharge
- Information transfer in binary form
What are the two main types of capacitors?
- Electrolytic capacitors
- Parallel plate capacitors
What is an electrolytic capacitor?
A Swiss-roll design of two plates separated by a dielectric material (such as mica, paper or ceramic). The distance between the plates and dielectric material produces the desired capacitance. It allows large capacitance in a very small size.
What is a dielectric material?
A non-conductive substance.
What are parallel plate capacitors?
A simpler formation of two plates separated by a dielectric material. Once a potential difference is applied, the plates of the capacitor charge up.
What are the factors affecting the desired capacitance of a parallel plate capacitors?
- Distance between plates (Increased distance -> decreased capacitance)
- Dielectric material (Increased permittivity -> increased capacitance)
- Common area of overlap between plates (Increased area -> increased capacitance)
How would you demonstrate the factors affecting a parallel plate capacitor?
Using parallel plate capacitors conected to a voltmeter and changing the factors one by one.
How would you demonstrate charging a parallel plate capacitor?
Set up a circuit with a battery, capacitor and switch, let the plates charge, replace the battery with a bulb, bulb will flash.
Give some uses of capacitors.
- Disposable camera bulb
- Filtering frequencies
- Tuning circuits
- Flash guns
- Smoothing circuits
