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Resistor - Basic Electrical Component I

Definition:

 It is a two terminal passive electrical Component that resists the flow of current in circuit
Resistor 

How it Works:

It converts electrical energy into heart which will dissipated into Air

Uses of Resistor:

  • Reduce Current Flow
  • Adjust Signal levels
  • Divide Voltage
  • Bias Active Element

Unit of Measurement:

     Unit of Resistor is Ohm which is name after the scientist George Simon Ohm

Types of Resistor:

There are two main types of Resistor:
  • Linear Resistor 
  • Non-Linear Resistor 

Linear Resistor:

Linear Resistor is a resistor those Value changes with change in temperature and current 

Types of Linear Resistor:

  • Fixed Resistor 
  • Variable Resistor 

Fixed Resistor:

 In this the Value of Resistor is fixed it doesnot change with changes with temperature and Current 

Types of Fixed Resistor:

  • Carbon Film Resistor 
  • Wire wound Resistor 
  • Thin Film Resistor 
  • Thick Film Resistor 

Carbon Film Resistor:

  •  It is a type of insulating power made in the shape of rods and 2 metallic caps on both sides
  • These 2 ends are connected easily through soldering 
  • It has plastic cost consisting of different collects core indicating its resistance 
  • It is available in 1 Ohm to 25 Mega Ohm with a power rating of 1/4 watts to 5 watts
  • It is reliable and available easily
Carbon Film Resistor 

Wire wound Resistor:

  • In this the insulating core or rods are wrapped with wire
  • It is available in the power range of 2 watts to 100 watts with the resistance of 1 Ohm to 200 kilo Ohm 
  • It can withstand ipo 350℃ 
  • It is very costly and sensitive
Wire wound resistor 

Thin Film Resistor: 

The Film around the insulating material is very thin in this type of Resistor
Thin Film Resistor 

Types of thin Film Resistor:

  • Carbon thin Film Resistor 
  • Metallic thin Film Resistor 

Carbon Thin Film Resistor:

  • It consists of ceramic core as a substract
  • It was very thin resistive carbon layer
  • It has wide range of operating range

Metallic Thin Film Resistor:

  • It is similar to carbon Film resistor but the film is made up of aluminum, nickel, chomium 
  • It is tiny cheaper and reliable in operation 
  • Temperature coefficient is very low

Thick Film Resistor:

The film around the resistor is thick made it useful for wide range of higher power.
Thick Film Resistor 

Types of Thick Film Resistor:

  • Metallic oxide
  • Cermet oxide
  • Fusible

Metallic Oxide Resistor:

In this metallic oxide are used as a substract 

Cermet Oxide Resistor:

In this ceramic core is used as substract. In this resistor doesnot change with temperature and current 

Fusible:

It is a type of wire wound resistor used when circuit power rating exceeds the specific Value then it breaks or open the circuit 

Variable Resistor:

The resistance of the resistor changes with change in its temperature and current 

Types of variable resistor:

  • Potentiometer
  • Rheostat
  • Trimmer

Potentiometer:

It is s three terminal device used for controlling the levels of Voltage in circuit 

Rheostat:

It is a two or three terminal device used for limiting Current. The current can be limited by hand or manual operation. It is also called tapped Resistor 

Trimmer:

It is a additional screw with potentiometer or variable resistor for better efficiency and operation. It is available in the range of 50 to 50 Mega Ohm and power rating of 1/3 watts to 3/4 watts 

Non-linear Resistor:

Its resistance changes abruptly with change in temperature and current 

Types of Non-Linear Resistor:

  • Thermistor 
  • Variable
  • Photo resistor or Light Dependent Resistor (LDR)

Thermistor:

It is very sensible to temperature. It changes with change in temperature. There are two types of temperature change:
1.Negative Temperature Coefficient 
2. Positive Temperature Coefficient 

Negative Temperature Coefficient:
In this resistance is inversely proportional to temperature. Resistance increase with decreases in temperature 

Positive Temperature Coefficient:
In this resistance is directly proportional to the temperature. Resistance increase with increase in temperature 

Varistors(VDR):

It Eliminate the high transient voltages. It protect the circuit from high Voltage spikes where the Voltage across sensitive devices decreases with the level of Voltage to a secure level 

Photo Resistor or LDR:

In this resistance changes with change in light intensity. When the light falls on Resistor it increases the free carriers due to light energy on sema conductor. It has Negative Temperature Coefficient.

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