What is resistor

Resistors offers resistance to the flow of current represented by  "R" and its units is "Ohm".
Factors affecting Resistors-

1. Resistivity of a meterial.
2. Length:-  Resistance is directly proportional to length.
3. Cross sectional area:-  Resistance is inversely proportional to the cross sectional area (A).
4. Temperature:- all material change resistance by the same amount when temperature changes.

Type of Resistors:-

1. Fixed Resistors
2. Variable Resistors

Type of Fixed Resistors-  

1. Carbon
2. wire Wound
3. Fusible Resistors

Type of Variable Resistors-   

1. Rheostate
2. Potentiometer 

Carbon Resistors-  It is made of carbon and graphite mixed on the powered isolating materiel as a binder.

The resistence value is from 1 Ohm to 20 Ohm.

           Power rating is 1/4 , 1/2, 2 watt.

Wire wound Resistors-  The resistance wire is wrapped round and isolating core power rating 5 watt to 100 watt the wire may be tonguston or maganin.

Fusible Resistors-  When power rating is exceeded fusible resistors burn out used for dual purpos as a resistors and as a fuse wire.

Variable Resistors:-  It can be corben  or wire wound resistors. There  are two type of variable resistors.

Measurement:-  Measure the value with the equipment.

Example:-   Multimeter