ONLINE ELECTRICAL ENGINEERING STUDY SITE

Carbon Composition Resistor

The resistance is a device which is used to oppose or minimizing the current flow in a circuit. The resistor offers a voltage drop across it so that the voltage across the load is reduced so that the voltage across the load is reduced and hence the current flow is reduced. The resistor can be made in many ways, we can make a resistor by using a wire which has high resistivity. In order to make the resistance almost constant, we select the material which has the low temperature coefficient. But the main disadvantage of doing this is that the power loss is more and also the cost increases. Its size also increases and the resistor will not be economic. So in order to remove that disadvantage, we use carbon resistor. These resistors have very small size as well as less power loss. Also, the resistor can have very high value up to a few mega Ohm.

These are so small that we cannot even indicate the value. For that we use color codes.carbon resistor

Construction of Carbon Resistors

They are made of carbon clay and leads are constructed of tinned copper. It is enclosed in plastic case so that there will be no entry of moisture and other harmful particles in the resistor. They have diameters less than 10 mm. For higher power dissipation the size of the resistor should be increased. The shape of the resistor is of cylindrical type. construction of carbon resistors

Color Code of Carbon Resistors

The color coding is provided since its size is too small and hence we cannot indicate the value of the resistor in the plate. The color code is as follows - color code of carbon resistor There are two types of color codes that we use -
  1. General Color Coding.
  2. Precision Color Coding.

General Color Coding

They are used if it has four bands and also they are used in the case of general purpose resistor. They have tolerance of ±5% or more. four band resistor To calculate resistance value, see the color of first digit and number it according to color code. Next, take the second color code and indicate the digit according to the color code. Third band is the multiplier band so put that the power of ten and multiply it with the previous number we got from the two digits, that will indicate the value and for tolerance see the fourth band and indicate the tolerance accordingly.
For example, if a resistor has a color code of Brown, Grey, Brown and Gold then the first digit we get is 1 as the brown indicates the digit 1.
Secondly the second band indicates the code to be 8. So the number we got from those two digits is 18.
Third band indicates the multiplier the multiplier so the multiplier is 10 as brown indicates 1.
Fourth band indicates the tolerance value, Gold has the tolerance of ± 5 %. So the resistance value we got is 180 ± 5 %.

Precision Color Coding

In this case we have five bands to indicate the resistor value. The first band is not black as in case of general purpose resistor. The only difference from the general resistors is that it has five bands and the first three will indicate the value, fourth one will indicate the multiplier and the last color indicates the tolerance value. They have the tolerance less than ± 2 %. So the color code is used accordingly. five band resistor

Advantages of Carbon Resistors

  1. They are cheap.
  2. They have small size.

Disadvantages of Carbon Resistors

  1. They are noisy.
  2. The power dissipation capacity is small.
Conclusion
The carbon resistor is very widely used in electronic circuits and integrated circuits due to their small size. They can be used to make electronic circuits because the circuits will require a very small current so the carbon resistor can handle safely. They are very sensitive to temperature changes. Also the small power handling capacity is the main drawback of these types of resistors. Also, these types of resistor tend to produce noise. Due to these they reasons they cannot be used in all the electric circuits but due to their low cost and small size, they are very popular.




Comments/Feedbacks






Closely Related Articles Types of Resistor Carbon Composition and Wire Wound ResistorVaristor Metal Oxide Varistor is Nonlinear ResistorWire Wound ResistorVariable Resistors | Defination, Uses and Types of Variable ResistorsLight Dependent Resistor | LDR and Working Principle of LDRMore Related Articles Electric Current and Theory of Electricity | Heating and Magnetic EffectNature of ElectricityDrift Velocity Drift Current and Electron MobilityElectric Current and Voltage Division RuleRMS or Root Mean Square Value of AC SignalWorking Principle of a CapacitorQuality Factor of Inductor and CapacitorTransient Behavior of CapacitorCylindrical CapacitorSpherical CapacitorCapacitors in Series and ParallelHow to Test Capacitors?Electrical Conductance Conductivity of Metal Semiconductor and Insulator | Band TheoryWhat is Electrical Resistance?Resistivity and Laws of ResistanceProperties of Electric ConductorTemperature Coefficient of ResistanceResistance Variation with TemperatureSeries ResistanceActive and Passive Elements of Electrical CircuitElectrical DC Series and Parallel CircuitOhm's Law | Equation Formula and Limitation of Ohm's LawKirchhoff Current Law and Kirchhoff Voltage LawSingle and Multi Mesh AnalysisSuperposition TheoremThevenin Theorem and Thevenin Equivalent Voltage and ResistanceNorton Theorem | Norton Equivalent Current and ResistanceReciprocity TheoremNodal Analysis in Electric CircuitsMaximum Power Transfer TheoremDelta - Star transformation | Star - Delta TransformationMagnetic FieldMagnetic FluxMagnetic PermeabilityHysteresis LoopMagnetic Field and Magnetic Circuit | Magnetic MaterialsMagnetic SaturationEnergy Stored in a Magnetic FieldStatic Electric Field | Electrostatic Induction A Current Carrying Conductor Within A Magnetic FieldMagnetic SusceptibilityHard Magnetic MaterialsSoft Magnetic MaterialsMagnetic Circuit with Air GapElectric ChargeCoulombs Law | Explanation Statement Formulas Principle Limitation of Coulomb’s LawElectric Lines of ForceWhat is Electric Field?Electric Field Strength or Electric Field IntensityWhat is Flux? Types of Flux?Electric FluxElectric PotentialCapacitor and Capacitance | Types of CapacitorsEnergy Stored in CapacitorCharging a CapacitorDischarging a CapacitorFourier Series and Fourier TransformTrigonometric Fourier SeriesAnalysis of Exponential Fourier SeriesParity GeneratorElectric Circuit and Electrical Circuit ElementsSeries Parallel Battery CellsRL Series CircuitWhat is Inductor and Inductance | Theory of InductorRLC CircuitThree Phase Circuit | Star and Delta SystemRL Parallel CircuitRL Circuit Transfer Function Time Constant RL Circuit as FilterConstruction of AC Circuits and Working of AC CircuitsSeries RLC CircuitParallel RLC CircuitResistances in Series and Resistances in ParallelResonance in Series RLC CircuitPlanar and Non Planar Graphs of CircuitClipping CircuitMutual InductanceSelf InductanceSI System of UnitsElectrical International SymbolElectric Power Single and Three Phase Power Active Reactive ApparentVector Algebra | Vector DiagramRelationship of Line and Phase Voltages and Currents in a Star Connected SystemVector Diagram | Three Phase Vector DiagramSource of Electrical EnergyVoltage SourceIdeal Dependent Independent Voltage Current SourceVoltage or Electric Potential DifferenceVoltage in SeriesVoltage in ParallelVoltage Drop CalculationVoltage DividerVoltage MultiplierVoltage DoublerVoltage RegulatorVoltage FollowerVoltage Regulator 7805Voltage to Current ConverterNew Articles Collecting Oil Sample from Oil Immersed Electrical EquipmentCauses of Insulating Oil DeteriorationAcidity Test of Transformer Insulating OilMagnetic FluxRing Counter