Resistance is an effect offered by a resistor that opposes the current while reactance is the effect offered by a capacitor or inductor that opposes the change of current.
The basic characteristic of resistance and reactance in an electrical circuit is that they restrict current flow. But the main difference between them is that resistor is a property that restricts the flow of current while reactance measures the restriction to the change of current.
Reactance vs Resistance
Resistance indicates the property of the resistor only but reactance can be the property of the inductor or capacitor. And the resistance and the inductance combinedly form an impedance.
Type of the Circuit
You can find the property resistance in both ac and dc circuits. But we can find inductance only in ac circuits. As we have mentioned earlier, reactance is associated with the change of current. And the change of current is only possible in ac circuits.
Symbol and Unit
The symbol of resistance is R and its unit is Ω. In the case of reactance, the symbol is X and the unit is Ω
Relation with Frequency
To understand the relationship between frequency and resistance or reactance, at first, we will have to observe the mathematical equations of them
Relation Between Frequency and Resistance
Resistance is simply equal to voltage divided by current R=VRI
Where VR = Voltage across resistor and I= Current through the resistor
As a result, frequency has no impact on resistance.
In the case of reactance, there comes two terms. Inductive reactance which occurs in an inductor (L) and Capacitive reactance which occurs in the capacitor (C)
Relation Between Frequency and Inductance
The equation of inductive reactance is XL=2πfL
Where, XL= Inductive reactance (Ω)
f= Frequency (Hz)
From the above equation, It is clear that Inductive reactance is proportional to the frequency
Relation Between Frequency and Capacitance
The equation of capacitive reactance is XC=12πfC
Where, XC=Capacitive reactance (Ω)
So the capacitive reactance is inversely proportional to the frequency
The resistance of any conductor depends upon the resistivity, temperature, and dimension of that conductor whereas reactance depends on the frequency of the alternating current.
Phase Difference Between Voltage and Current
In the case of resistance, the voltage is in phase with the current and the phase difference between them is zero. For inductive reactance, the voltage leads the current by 90 degrees. And for capacitive reactance, the voltage lags the current by 90 degrees. So the phase difference between voltage and current is 90 degrees in case of reactance.
In resistors, the power dissipates in the form of heat. But inductors and capacitors are power storing elements. They store a part of supplied power.
How is resistance related to Reactance?
As we have mentioned earlier that in terms of functioning in a circuit, resistance and reactance are the same things and their nature is also the same. Cause both of them try to oppose the flow of current.
Frequently Asked Questions
How to convert resistance to reactance?
To know the answer to this question we will have to know the term “Impedance”. Impedance is the combination of resistance and reactance. Let, in a circuit Impedance is Z, Resistance is R, and Reactance is X. Then the formula of Impedance will be
It will be clear if we see an example.
Let in a circuit, the value of resistance is 10Ω and the value of reactance is 15Ω. Then what will be the value of impedance Z ?
Here, Z will be 102+152=18.03Ω
Thus if we know the value of any two terms among resistance, inductance, and capacitance then we can easily calculate the value of other term.
So it is clear that in terms of functioning, resistance and reactance are relatable, but they are completely different term in many aspects. And they combinely form impedance.