Resistor | Types of Resistor | Resistance calculation using multimeter


It is a Two-terminal electrical/electronic component that has the nature of the Resistance. A Resistor is a purely electronic/electrical resistive component that opposes the flow of electrons. The measure of voltage across the resistor’s terminals is called a “voltage drop” across the resistor. Voltage drop is proportional to the resistance value, If there is any change in resistance value then the voltage drop also changes



V = IR (Ohm’s Law)


NOTE: So In any design, these are used to voltage, manipulation to get the required rated voltage.

ØIt is a passive device
ØIt has no polarities
ØUnits: ohm (Ω)

    Resistor values: 10kΩ, 100Ω, 1 MΩ    Power Resistors 


  •  Type: Carbon Film Leaded resistor
  • The most economic industrial investment
  • Standard tolerance: +/-5%
  •  Excellent long term stability
  • Termination: Standard solder-plated copper lead

Resistance Calculation:

    Resistor Color Code: Resistor color code


Resistor watts: 1/4 watt, 1/2 watt,1 watt, 2-watt Resistors.

The selection of the resistor depends on how much current flow in your design, If more current will flow in your design high wattage resistor is required 

NOTE: Resistors are available as the same wattage with a different type of resistance values. 

How to check the resistance using Multimeter

 Set the Multimeter red wire is connect at voltage position and Black wire is connected at the Ground (GND) of a multimeter. Now Consider your resistance value will be 10kΩ,  place the multimeter knob at the range of 10kΩ in a multimeter and connect a multimeter probes led pins to terminals of the resistor, then multimeter shows the resistance value in the display may be if it showed ‘1’  number  it means that resistance is out of the range, you need to change the resistance range in the multimeter.

 Note: Resistor has no polarities you can connect in any terminals.  

Series and parallel Resistance:

Series Resistance:

  •  In a series connection total resistance will be the sum of all resistors
  • We observe unique current flow in series connection
  • Resistors-Series connection-TechnoElectronics44rr
    Resistor Series connection

  • The voltage will be divide across each resistor – Total voltage drop  equal to the sum of the voltage drop across individual resistors                     

Series connection: Voltage vs Current-TechnoElectronics44
Resistor-Series connection: Voltage vs Current

     Parallel Resistance:
  • In parallel connection total resistance will be reduced
  • We observe the same voltage drop-in each Resistor
  • Current will be divide across each resistor – Total current  is equal to sum of current flow  across each resistor  
Resistors-Parallel connection-TechnoElectronics44


Parallel Connection: current vs voltage-TechnoElectronics44
Resistor-Parallel Connection: current vs voltage

Basic types of Resistors

  • Fixed Resistors
  • Variable resistors

Fixed Resistors:

The value of Resistor is not changed or we can say that the resistance can not be influenced by any parameter (example: heat light, intensity), and also we are not able to change the resistance value manual.

  • These are again classified into different types such as
  • Carbon composition 
  • Film carbon type
  • Carbon film type
  • Metal film resistor
  • Metal oxide film resistor
  • Wire wound resistor
  • Surface mount resistor

Variable Resistors

 The resistance of the Resistor changes by manual or automatic. We can change the resistance value from minimum to maximum value, this way we can change and fix at a particular position.

For example, we have a 100k variable resistor, we can change it from 0Ω - 100KΩ  and fix it at any resistance value (ex:20kΩ).

  • Preset
  • Potentiometer (Pot)
  • Trim-pot

Other types of Resistors


All sensors have the resistance property, so we can say that sensors are one of the parts of the variable resistors.


  • Thermister (NTC, PTC)
  • Light dependant Resistor
  • Digital potentiometer


Power resistors

Power resistors are designed to withstand a large amount of power and dissipate a large amount of power. Power resistors are mostly used in industries, power plants, or any application that can handle the high power ratings. Power resistors are made from a material that has high thermal, conductivity that allows efficient cooling with heat sink elements.

·         Wire wound resistors

·         Grid resistor

Applications of power resistor

  • Engine braking
  • Load bank
  • Neutral grounding resistor


H    How to select the Resister

Fi    First, you have to study about your requirement

R    Resistors selection Factors

  • Resistance
  • Power dissipation
  • Wattage(Voltage and current)
  • Thermal range



  • In any circuit design, we are using resistors
  • electronics products design
  • Electrical products design
  • Design of Industry applications


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