# Difference between Electric Circuit and Magnetic Circuit

A circuit is a type of network having a closed path for the flow of either electric current or magnetic flux. A circuit mainly consists of three major parts viz. source, path or conductor and load. In simple words, the term circuit can be used to represent any fixed path through which electricity, data, single or magnetic flux can flow.

Depending on the type of quantity (electric current or magnetic flux), the circuits can be of two types as −

• Electric circuit

• Magnetic circuit

In this article, we are going to see the differences between electric circuit and magnetic circuit. Also, we have added a short description of electric circuit and magnetic circuit for your reference.

## What is an Electric Circuit?

An electric circuit is a closed path through which electric current can flow. A typical electric circuit consists of three main parts namely, energy source such as cell, battery, generator, etc., connecting wires, and loads such as lamp, fan, etc.

Depending upon the type of current flowing in the circuit, the electric circuit is classified into two types as −

• DC circuit (a closed path followed by direct current)

• AC circuit (a closed path followed by alternating current)

Based on the arrangement in which the circuit elements are connected, the electric circuit can be classified into three types as −

• Series circuit
• Parallel circuit
• Series and parallel circuit

## What is a Magnetic Circuit?

A magnetic circuit is a closed path through which magnetic flux (or magnetic field lines) can flow. A typical magnetic circuit consists of a core of highly permeable magnetic material such as soft steel, around the core a winding is placed to produce the magnetic flux in the core.

The magnetic circuits are the basic building blocks of various electrical devices such as generator, motor, transformer, measuring instruments, etc. The magnetic circuits are classified into two types as −

• Series magnetic circuit

• Parallel magnetic circuit

A magnetic circuit in which only one path is provided for magnetic flux to flow is known as series magnetic circuit. If there are more than one path for magnetic flux to flow, then it is known as parallel magnetic circuit.

## Difference between Electric Circuit and Magnetic Circuit

The following table highlights the major differences between electric and magnetic circuits −

ParameterElectric CircuitMagnetic Circuit

ParameterParameterParameter
DefinitionA closed path followed by electric current is known as electric circuit.A closed path followed by magnetic field line or magnetic flux is known as magnetic circuit.
Circuit quantitiesIn electric circuit, the major quantities associated with the circuit are EMF, voltage, current, resistance, capacitance and inductance, etc.The fundamental quantities associated with magnetic circuits are MMF, magnetic flux, reluctance, etc.
Quantity flowing in the circuitThe electric current is the quantity which flows in an electric circuit.The magnetic flux is the quantity which flows in a magnetic circuit.
Expression of Ohm’s lawFor electric circuit, Ohm’s law is as −
$\mathrm{Current,\mathit{I}\, \mathrm{=}\, \frac{EMF}{Resistance}}$
For magnetic circuit, the expression of Ohm’s law is −
$\mathrm{Magnetic\: flux,\phi \, \mathrm{=}\, \frac{MMF}{Reluctance}}$
Driving forceThe EMF or electromotive force is the driving force in an electric circuit, which creates potential difference so that current can flow in the circuit.In case of a magnetic circuit, the MMF or Magnetomotive force is the driving force, which causes the flow of magnetic flux in the core of the magnetic circuit.
OppositionThe resistance of the electric circuit opposes the electric current flowing in the circuit.The reluctance of the core of magnetic circuit opposes the flow of magnetic flux in the circuit.
Measure of oppositionIn an electric circuit, the resistance opposes the flow of current, which is given by,
$\mathrm{\mathit{R\, \mathrm{=}\, \frac{\rho l}{a}\,\Omega }}$
In a magnetic circuit, the reluctance produces the opposition in the flow of magnetic flux, which is given by,$\mathrm{\mathit{S\, \mathrm{=}\, \frac{ l}{\mu a} }\; AT/Wb}$
Reciprocal of oppositionIn an electric circuit, the resistance produces the opposition whose reciprocal is known as conductance and is given by,$\mathrm{Conductance,\mathit{G\, \mathrm{=}\, \frac{\mathrm{1}}{R} }}$
In a magnetic circuit, the opposition to the magnetic flux is reluctance whose reciprocal is known as permeance, and is given by,$\mathrm{Permeance \, \mathrm{=}\,\frac{\mathrm{1}}{Reluctance}}$
DensityThe electric current flows in an electric circuit whose density (called current density) is given by,$\mathrm{\mathit{J\, \mathrm{=}\, \frac{I}{a}}\: A/m^{2}}$
Magnetic flux flows in a magnetic circuit whose density, called magnetic flux density, is given by,$\mathrm{\mathit{B\, \mathrm{=}\, \frac{\phi }{a}}\: Wb/m^{2}}$
Field intensityIn an electric circuit, electric field exists whose field intensity is given by,$\mathrm{\mathit{E\, \mathrm{=}\, \frac{V }{d}}}$
In a magnetic circuit, there is a magnetic field whose intensity is$\mathrm{\mathit{H\, \mathrm{=}\, \frac{NI }{l}}}$
DropThe voltage drop occurs in an electric circuit due to resistance which is given by,$\mathrm{Voltage\: drop\: \mathrm{=}\: \mathit{IR}}$
MMF drop occurs in a magnetic circuit due to reluctance of the magnetic path which is given by,$\mathrm{MMF \: drop\: \mathrm{=}\: \phi \times \mathit{S}}$
Change in the oppositionIn an electric circuit, resistance is the opposition whose value remains almost constant as its value depends upon the physical properties such as area, length, resistivity, etc. of the conductor that are also constant. However, the value of resistance may change slightly due to change in temperature.The opposition in a magnetic circuit is due to reluctance of the circuit whose value varies with change in magnetic flux density (B).
InsulatorA large number of perfect insulators are there for an electric circuit such as air, glass, mica, wood, etc. which do not allow electric current to flow through them.There is no perfect insulator for the magnetic flux. The magnetic flux can also set up in a non-magnetic material like air, rubber, etc.
Energy required in the circuitIn an electric circuit, the energy must be expended continuously as long as the electric current flows.In a magnetic circuit, once the magnetic flux is set up in the circuit, no energy need to be expended.
Circuit lawsThe Ohm’s law for electric circuit, KVL and KCL are followed in an electric circuit.The Ohm’s law for magnetic circuit, Kirchhoff’s MMF law and Kirchhoff’s flux law are followed in a magnetic circuit.
Direction of field linesThe direction of electric field lines is from positive terminal to the negative terminal in the electric circuit, i.e. the electric field lines starts from positive charge and ends on the negative charge.The magnetic field lines starts from north pole and ends on the south pole.

## Conclusion

In this article, we described the various differences between magnetic and electric circuits by considering various parameters such as definition, circuit quantities, expression of Ohm’s law, driving force, opposition, field intensity, drop, insulators, and direction of field lines, etc.