70uH 5A IRON POWDER INDUCTOR (USED)

This specification describes a versatile power inductor commonly used in DC-DC converters, EMI filtering, and energy storage applications.

An iron powder core is a "distributed air gap" material.¹Unlike ferrites, which saturate abruptly, iron powder offers a soft saturation curve, meaning the inductance decreases gradually as current increases beyond its rated limit.

• Inductance (L):70uH (microhenries).

• Current Rating (I_DC):5A (continuous).

• Core Material: Iron Powder (e.g., Mix #26 (yellow/white) or Mix #52 (blue/green)).

• Energy Storage (E):E = \frac12 L I^2  approx 0.875mJ.

The primary advantage of iron powder is its ability to handle "surges" without losing all inductive properties. If you push 6A or 7A through this 5A part, it might drop to 55uH or 60uH rather than dropping to zero like a ferrite core would.

• Pros: Low cost and high flux density (B_sat up to 1.5T). This allows for a very compact size for a 5A rating

• Cons: Higher core losses at very high frequencies (typically used below 250kHz). If used in a 1MHz switching regulator, the iron powder core may become quite hot due to eddy currents.

Because the magnetic flux is contained within the toroidal (donut) shape, it has very low electromagnetic interference. This makes it an excellent choice for a Differential Mode Choke in power line filters to clean up noise before it reaches the rest of your circuit.