THEORY 20.1 :- CAPACITOR COLOR CODE

 

A Capacitor stores electric charge. Basically a capacitor consists of two metal plates separated by an insulating material called “dielectric”. When connected to a power source such as battery, the capacitor charges up until the potential difference between its terminals become equal to the e.m.f of the battery.

The capacitance of the capacitor is its ability to store charge and is measured in terms of Farads. The capacitance depends on the area of the plates and the distance between them and also the type of dielectric used.

Capacitance = Q / V

Where Q is the charge and V is the voltage.    
Thus the capacitance is the charge divided by voltage.

The important parameters of the capacitor are

1.     Value 

Value is marked on the capacitor directly or in colour codes

2.     Tolerance

It indicates how much more or less the actual capacitance of the capacitor

3.     Working voltage

It is the maximum voltage a capacitor can withstand before the dielectric breakdown

4.     Leakage current

There is always small leakage current in all capacitors. Ideally this should be zero. But no capacitor is perfect without leakage current. Tantalum capacitor is comparatively better with minimum leakage current

    Colour coding

        Like resistors, some capacitors are colour coded to indicate value, tolerance,  working voltage etc. These colour bands are numbered from the top of the   capacitor to the base. The colour coding is similar to 

    Resistor colour coding

 

    Capacitor color code

• First band – First number of colour code chart
• Second band – Second number of colour code chart
• Third band – Number of Zeros
• Fourth band – Tolerance (Black 20%, White 10 % and Green 5 %)
• Fifth band – Appears as body colour. Working voltage (Red 250V, Yellow 400 V)

    Colour code of Resistor