Enter the inductance of the coil and the resistance of the circuit into the calculator to determine the inductive time constant. This calculator helps in analyzing the transient response of inductive circuits.

Inductive Time Constant Formula

The following formula is used to calculate the inductive time constant (τ).

τ = L / R

Variables:

  • τ (tau) is the inductive time constant (seconds)
  • L is the inductance of the coil (henries)
  • R is the resistance of the circuit (ohms)

To calculate the inductive time constant, divide the inductance (L) by the resistance (R).

What is an Inductive Time Constant?

An inductive time constant is a measure of the time it takes for the current in an inductive circuit to reach approximately 63.2% of its maximum value after a change in voltage. It is a key parameter in the analysis of transient responses in inductive circuits, such as when a switch is closed or opened. The time constant is determined by the inductance and resistance in the circuit and is denoted by the Greek letter τ (tau).

How to Calculate an Inductive Time Constant?

The following steps outline how to calculate the inductive time constant.


  1. First, determine the inductance of the coil (L) in henries.
  2. Next, determine the resistance of the circuit (R) in ohms.
  3. Use the formula τ = L / R to calculate the inductive time constant (τ) in seconds.
  4. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem :

Use the following variables as an example problem to test your knowledge.

Inductance of the coil (L) = 0.5 henries

Resistance of the circuit (R) = 200 ohms