What is the Difference Between Equivalent Resistance and Effective Resistance?

The main difference between equivalent resistance and effective resistance lies in their definitions and the factors they depend on:

1. Equivalent Resistance: This refers to the single resistance value that can replace a group of resistors in a circuit, offering the same overall resistance. Equivalent resistance is a purely resistive property and does not change with any other variable. It is calculated using the concept of total voltage and total current in series and parallel combinations of resistances.
2. Effective Resistance (Impedance): This is another name given to impedance, which is a property that changes with the frequency of the signal. Impedance is defined as the resistance to an alternating current, expressed as the ratio of the power dissipated to the square of the effective current. Effective resistance varies with the frequency of the signal, and for passive devices such as resistors, it is always constant.

In summary, equivalent resistance is a purely resistive property used to simplify circuit analysis, while effective resistance (impedance) is a property that changes with frequency and is used to describe the behavior of a circuit with respect to alternating current.

Comparative Table: Equivalent Resistance vs Effective Resistance

The difference between equivalent resistance and effective resistance can be understood through their definitions and applications in circuit analysis. Here is a table comparing the two concepts:

In summary, equivalent resistance refers to the static resistance property of a load across a potential difference, while effective resistance represents the total resistance of a collection of resistors in a specific arrangement, such as series or parallel connections. These two concepts are used in different contexts and are calculated using different formulas.