diff --git a/source/electronics/metrics.rst b/source/electronics/metrics.rst
index a934413..b91a9b1 100644
--- a/source/electronics/metrics.rst
+++ b/source/electronics/metrics.rst
@@ -76,6 +76,10 @@ Ohm defines the amount of volts required at one end of the resistor to pass one
 
 Henry
 ^^^^^^^^^^
+An inductor is resisting to change in current.
+When current is changing, a voltage appears at the inductor terminals.
+Henry corresponds to the voltage measurable across the inductor terminals when the current is changing at a rate of one ampere per second.
+
 
 .. math::
    H=\Omega.s=\frac{kg.m^2.s^{-3}.[A]^{-1}}{[A]} \times s = \frac{m^2.kg}{s^2.[A]^2} = m^2.kg.s^{-2}.[A]^{-2}