Introduction: –
Capacitor is an electric charge collector device. In other way we can say that it is a device which is collect electric power in form of electric charge. Mostly we use this capacitor to collect AC voltage but there are some types of capacitors which is also collect DC voltage.
There are many types of capacitors like AC capacitor, DC capacitor, spherical capacitor, cylindrical capacitor, parallel plate capacitor, electrolytic capacitor and variable capacitor.
But in this post, we will discuss about multiplate or variable capacitor.
Multiplate or variable capacitor: –
Generally, we know the capacitor with two plate and filling with dielectric material. But as the name depicts that there are many numbers of plate in the variable capacitor.
Dielectric material is filled between every two plates. In this capacitor half numbers of plates are fixed plate which are not moveable. And remaining half numbers of plate are moveable plate. This moveable plate control by a knob.
Capacitance of this capacitor can be varied by moving knob. The main of the capacitor is to vary the value of capacitance. That’s why this capacitor’s name is ‘variable or multiplate’ capacitor.
When the variable plates displace or drag to outer side completely, then we found the minimum capacitance value of this capacitor. And when we move this variable plate towards inner side, we found maximum capacitance value of this capacitor.
This value varies because when we decrease the distance between two plates capacitance will increase. And when we increase the distance between two plates, capacitance will decrease.
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Uses of variable capacitor: –
Generally, this type of capacitors is used, where there is need to be change of capacitance value instantly. And also, when we have to change the frequency, variable capacitor is suitable for this.
That’s why multiplate or variable capacitors are use in radio system. In radio system we need to change the frequency time to time. So that, we can hear sound of there’s frequency.