resistor and its color code

Resistor

fig:-Resistor

Resistor is the common electrical component which is used to resists the flow of the electron.
The value of the resistance is measure in ohms (Ω),here the resistance is measured by using ohm law when the current is known and voltage drop is measure by using the following relation.
V=I*R
where V= Voltage
           R= Resistance
           I= Current

fig:- Symbol of resistor.

Resistor color code:-

   Components and wires are coded with color to identify the specific value of the resistor.

Resistor are of various type according to the band type i.e 4 color band,5 color band,6 color band.

Here in the 4 color band first two band are digit,third one is multiplier and last one is tolerance.In the absence of last band we use 20% tolerance in 4 band.

 In 5 band first three color band are digit,fourth band is multiplier and the last one is tolerance.

The increase space between third and forth band indicate the reading direction.Further more gold cannot be in the first band.

Examples

  

 Here the first two resistor orange and blue which is digit and the third one is red which  is multiplier  and the last one is tolerance.

first two color are digit and third one is multiplier.  

 +/-5% =3.6KΩ

so from above chart, value = 36*100 +/-5% =3.6KΩ

Here the first two resistor are orange color,third one is white & forth one is black with the tolerance of brown color.

so, from above chart its value=339*1+/-1%= 339Ω+/-1%

Resistance in series

If the resistor are arrange in a chain order then it is said to be connected in series which is shown in below figure.The current is same through each resistor.

Now calculating current(i):-

equivalent resistance(R)=R1+R2+R3

                                      =50+40+10

                                      =100 

Using ohms law V=I*R

                           I=0.1ampere

Resistance in parallel

If the one end of the resistor are connected to one common point and another end at other comman point  the the resistor are said to be connect in parallel.

Now calculating current(i)

Equivalent resistance (1/R)=1/R1+1/R2+1/R3

                                        =1/50+1/40+1/10

                                1/R  = 0.145

                                  R=6.89

Now  current "i" beror dividing is given by ohms law i=V/R

                                                                                       =10/6.89

                                                                                       =1.45A

Again current for individual resistor

i1=V/R1

   =10/50

   =0.2A

i2=V/R2

   =10/40

   =0.25A

i3=V/R3

  =10/10

  =1A

so finally the sum of i1,i2,i3 is equal to i.