Inductors in DC Circuits
Test: The DC voltage at the coil is switched on and off. The voltage curve at the coil and the current are measured.
If the voltage at the coil is switched off, this means a large change in current. The coil reacts to this and induces a voltage, the so-called self-induction voltage, which counteracts the change in current. In other words: The coil tries to maintain the current flow.
A coil has an inductance L of 1 H (pronounced "Henry") when a self-induction voltage of 1 V is generated in one second with a constant change in current of 1 A.
Formula symbol Inductance: L Unit: Henry H or Ωs
Note: The term inductance is also generally used as an umbrella term for the coil.
Caution when switching off inductors! The self-induction voltage can be several times higher than the supply voltage!