Basic Components - Resistors

Resistor: 

As we had seen in the basic circuit, addition of a resistor in the circuit limited the flow of current. This was indicated by the LED glowing dimmer when a resistor was introduced. It is obvious that higher resistance limits current flow to the maximum. This can be observed by playing around using different resistors.

Identifying Resistor values:

Resistor value is identified by the colour code in it. There are many sites that teach you how to calculate the value of a resistor. 

Color                         Value

Black                          0                                      
Brown                         1                                     
Red                             2                                     
Orange                        3                                     
Yellow                         4                                      
Green                         5                                       
Blue                            6                                       
Violet                          7                                       
Grey                           8                                       
White                          9                                      

Gold / Silver colour at the end indicate the tolerance of resistor and are +/- 5% and +/- 10% respectively. This indicates that the value of resistor used will be within the range R-5% to R+5% if it has a gold band.

In case of tri-band resistor, the first 2 colour bands indicate the significant digits and the last colour band indicate multiplier.

In case of 4/5 band resistor, the last colour band indicates the multiplier and a similar calculation can be used to compute resistor value.

Example:

Lets quickly identify the value of a resistor that is coloured in the following order

Black                          0                                      
Brown                         1                                     
Red                             2                                     


=(10) X (100)
=1000 Ohm
=1Kilo Ohm

Yellow                         4                                     
Violet                          7                                      
Red                             2                                                 



=(47) X (100)
=4700 Ohm
=4.7 Kilo Ohm