DIY Home Made Capacitors (Paper Capacitor and Its Theory)

Here in this blog I explain something about capacitors and teach you to make a simple capacitor in your home. So, first we discuss about capacitors and then about the DIY capacitor making.

Capacitor

Basically what is a capacitor? It is a basic electronic component which stores electrical energy. It is a passive device. It has only two leads. It is used in circuits to filter the AC signals. It is commonly used in rectifier filter circuits and in audio RF filter circuits and also in resonance circuits. In resonating circuits it act as a frequency selecting device. These are the common details about capacitors.

Capacitor is made by placing an insulating dielectric material between the two electrically conducting plates. When connecting a voltage source (battery) to the capacitor, the plates become oppositely charged and there create an electric field in-between the two plates. The energy is stored in the produced electric field between plates. When the battery removed, there is nothing happen. The energy is still appear in the electric field. So in capacitors the energy is stored in the direct electric form. But in batteries the energy is stored in the form of chemical energy. It is the major difference between capacitor and battery.

Capacitor Equations

Equation are used to model the capacitors with the help of mathematics. It indicate the relation between different factors in capacitors like voltage, current, charge, etc... It is not electronics, it is just a tool to simplify the complexity of capacitors for everyone. Main equation are given above.

The first equation indicate the relation between capacitance and the capacitor physical dimensions. The constant in the equation is dielectric constant depend on the properties of the dielectric material. This equation tell that the capacitance is increases with increase in the area of plate and decrease with increase in the distance between the plates.
The second equation indicate the relation between current and voltage with the capacitance.

The capacitor is arranged in series and in parallel. In series arrangement the capacitance decreases and the voltage rating increases. In parallel arrangement the capacitance increases and the voltage rating still same. These are given in the figure given below.

Different type of capacitors

Electrolytic capacitor

1. Electrolytic capacitor It is commonly present in high capacitance value ranging from few micro-farads to 10000 micro-farads. It have polarity. The reverse polarity cause damage to it. The dielectric used here is an electrolyte, So it is known as electrolytic capacitor. Commonly it is used to store charges in capacitor. Thus it is used as filter capacitors in rectifiers.

2. Ceramic capacitors

It is made up of ceramic material as dielectric. Commonly it is available in small values ranging from pico-farads to nano-farads range. It have no polarity. Commonly it is rated for high voltages. Commonly it is used for filter application and in RF circuits. It is available in small sizes and also preset in SMD packages. 3. Tantalum capacitor These are high precision capacitors. It have polarity. It is marked on the surface. It is available in wide ranges. It is used for filtering purposes. Film capacitor4. Film capacitor It is a commonly used type. It is available in nano-farad ranges. It is good for filter applications in audio circuits. Commonly it is rated for high voltages. 5. paper capacitor Here the dielectric in between the plates is paper. Use aluminium sheets and paper sheets for constructing it. The alternate paper and aluminium sheets form a stack and it produce more capacitance than a single sheet. It available in small values. It is used for filters.

Capacitor Making

Now we are know something about capacitors. It never ends, I am still study about capacitor in every day. Here I plan to make a paper capacitor. From the name we get that the dielectric here is paper. The plan is given in the image. I use a magazine paper because it has a plastic coating. It decrease the leakage between the capacitor plates. The plates are made by using the aluminium foil. The procedure is given below,
Prepare the magazine paper and aluminium foil (cutting)Take a paper and stick the aluminium foil in each side by using glueConnect two wires from each aluminium foil sideInsulate the two plates by covering with two magazine paper in each side using glueRoll up the capacitor into a cylindrical shapeFinally add wrap some plastic stickers for finis it