- A Capacitor consists of two metal plates separated by a dielectric.
- The dielectric can be made of many insulating materials such as air, glass, paper, plastic etc.
- A capacitor is capable of storing electrical charge and energy.
- The higher the value of capacitance, the more charge the capacitor can store.
- The larger the area of the plates or the smaller their separation the more charge the capacitor can store.
- A capacitor is said to be “Fully Charged” when the voltage across its plates equals the supply voltage.
- The symbol for electrical charge is Q and its unit is the Coulomb.
- Electrolytic capacitors are polarized. They have a +ve and a -ve terminal.
- Capacitance is measured in Farads, which is a very large unit so micro-Farad ( uF ), nano-Farad ( nF ) and pico-Farad ( pF ) are generally used.
- Capacitors that are daisy chained together in a line are said to be connected in Series.
- Capacitors that have both of their respective terminals connected to each terminal of another capacitor are said to be connected in Parallel.
- Parallel connected capacitors have a common supply voltage across them.
- Series connected capacitors have a common current flowing through them.
- Capacitive reactance is the opposition to current flow in AC circuits.
- In AC capacitive circuits the voltage “lags” the current by 90o.
The basic construction and symbol for a parallel plate capacitor is given as:
Post a Comment