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Electronics Tutorial

Electronics for beginners

 
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Electronics Tutorial for Beginners

ABC of Electronics Offering free comprehensive basic electronics tutorial. In this Electronics Tutorial we have explained the basic electronic concepts. Here you can find 8051 Tutorials & 555 Timer Tutorials which are commonly used in electronics. Every effort is made to keep the website up and running smoothly

Resistors and Resistances

resistorsresistors

Resistors restrict the flow of electric current. They are also electronic components like we have transistors, diodes.

In other words resistors resist the flowing of current. We can put a resistor on our Circuit any way round.

Resistors resist the flow of electrical current. The higher the value of resistance (measured in ohms) the lower the current will be.

Resistors are color coded. To read the color code of a  4 band 1K ohm resistor with a 5% tolerance, we should start at the reverse side of the GOLD tolerance band and read from left to right.

As we know resistors have 4 bands. Below is the brief description of each band.

  • The first band gives the first digit.
  • The second band gives the second digit.
  • The third band indicates the number of zeros.
  • The fourth band is used to show the tolerance of the resistor

Resistor color codes

BLACK                  0

BROWN                 1

RED                       2

ORANGE                3

YELLOW                4

GREEN                   5

BLUE                     6

VIOLET                  7

GRAY                    8

WHITE                  9

For example let us take the below resistance

RESISTOR

BAND1:GREEN REPRESENTS 5

BAND2:RED REPRESENTS 2

BAND3:BLUE REPRESENTS 6(NUMBER OF ZEROES)  

BAND4:GOLD REPRESENTS TOLERANCE 5% AS MENTIONED IN BELOW TABLE.

SO AFTER ABOVE OBSERVATIONS CALCULATED VALUE OF ABOVE RESISTOR IS

52000000 OHMS=52000 KILO OHMS=52 MEGA OHMS

Tolerance is the precision of the resistor

Tolerance Colour
±1% brown
±2% red
±5% gold
±10% silver

Resistors are also used with transducers. Transducers are electronic parts which convert energy from electrical energy to another form of energy. A light dependent resistor, is an example of an transducer.

COMMON  TYPES OF RESISTORS

resist

        Carbon film resistors 

    This is the most general purpose resistor, a cheap resistor. The tolerance of the resistance value is ±5%. Power ratings of 1/8W, 1/4W and 1/2W are frequently used.
    Carbon film resistors act to be electrically noisy.

       Variable Resistors 

    The rotation angle of the variable resistor is usually about 300 degrees. Variable Resistors has an advantage that they give very precise and accurate adjustments of their value. These are also known as Potentiometers.

    GENERAL INFORMATION ON RESISTANCES

    The electrical resistance of a circuit component or device is defined as the ratio of the voltage applied to the electric current which flows through it:

    V=IR  OHMS LAW

    Resistance of a wire

    R=pL/A

    P=Resistivity, L=Length, A=Cross sectional area

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