An inductor is a coil of wire. When current flows through it, it creates a magnetic field that stores energy. The inductor resists changes in current — it takes time to "charge" the magnetic field when you apply voltage, and it kicks back (back-EMF) when you try to remove the current suddenly.
Inductance is measured in henries (H). Most coils in the Open Energy experiments are in the microhenry (µH) range.
Key properties
- More turns = more inductance (it increases with the square of the number of turns)
- A ferrite core dramatically increases inductance compared to air
- Every real inductor has parasitic capacitance between its windings, which gives it a self-resonant frequency
- Winding geometry matters — a bifilar coil has different resonant properties than a conventional coil, even with the same number of turns on the same core