Reactance depends on inductance. As I mentioned, this is a store-bought, radial-lead inductor. The inductance is in the spec sheet.

Don

 

Reactance, is a form of opposition that electronic components exhibit to the passage of alternating current because of capacitance or inductance. In some respects, reactance is like an AC counterpart of DC (direct current) resistance.

 

A saturated inductor is simply a hot piece of low-resistance wire with almost no inductance or reactance.

 

Just because it's saturated doesn't mean it doesn't have a magnetic field.

Of course!

It just doesn't increase much with added current past that point.

Past magnetic saturation point, it won't.

 

Thanks, Max. Actually, I was replying to the other poster who was saying that a saturated coil has neither inductance nor reactance, which is nonsense.

Don

Inductive reactance only occurs when AC is applied.
The opposition to current flow through an Inductor when AC is applied is called Inductive Reactance and which depends lineally on the supply AC frequency

 

that a saturated coil has neither inductance nor reactance, which is nonsense.

Not nonsense.
A saturated coil may have a magnetic field but it's inductance (and thus reactance) drops to zero.

 

Not nonsense.
A saturated coil may have a magnetic field but it's inductance (and thus reactance) drops to zero.

 

All of the preceding is "cute" - but the OP has not described much the electromagnetic function of these inductors
maybe High-performance core-shell-type FeSiCr@MnZn soft magnetic composites for high-frequency applications is what could be beneficial

 

All of the preceding is "cute" - but the OP has not described much the electromagnetic function of these inductors
maybe High-performance core-shell-type FeSiCr@MnZn soft magnetic composites for high-frequency applications is what could be beneficial

Remember the OP mentions pulsed DC which has quite a different effects to when AC is applied.

 

Reactance depends on inductance. As I mentioned, this is a store-bought, radial-lead inductor. The inductance is in the spec sheet.

Don

How about sharing the datasheet or part number of the inductor?

 

The current one is a Coilcraft RFC1010B-105KE. It's 10 mH and works for most frequencies, but requires a buck converter to limit the applied voltage. I'd like to eliminate the converter and use a coil that will run at Isat with the full 5V supply. Every coil is dedicated to a frequency and there are almost 100 of them. Space is critical and I'd like to stick with the form factor of the RFC1010 series.

Don

 

It's 10 mH and works for most frequencies,

"Frequencies" refers to AC, you are using pulsed DC.
A whole different outcome.

 

No it doesn't. If I pulse at 100 Hz that's a frequency. What are you talking about?

Don

 

My original question was what is the formula for inductive reactance for a square, DC wave. Several posters tried to tell me there is no reactance, but my measurements from previous experiments indicate that there is.

Don

 

If you capacitor-couple the DC pulses to the inductor then it gets AC and the peak current is half what it is with your DC pulses but the peak-to-peak signal level is the same.

Why are you overloading the inductor by saturating it? Use a larger inductor that does not saturate at the current you are using.

 

I'm using the inductor as an electromagnet. I want the maximum pull I can get from this small form factor. Driving it AC with a cap would double the pull frequency (it pulls with both polarities).

If I had a valid formula for X, I could go through the inductor catalog page and easily calculate what inductor I need to get Isat at 5V for each frequency I want to drive.

Don

 

No it doesn't. If I pulse at 100 Hz that's a frequency. What are you talking about?
Don

The characteristics when used with a DC pulse compared with an AC of the same frequency will be hugely different.

 

The characteristics when used with a DC pulse compared with an AC of the same frequency will be hugely different.

How about an example?

 

I think one way is to run it as like a buck converter
https://www.allaboutcircuits.com/te...ysis-of-four-dc-dc-converters-in-equilibrium/
at some frequencies and duty cycle there would pretty much be a 'constant' current across it.

the amount of heat generated may not be small,, it depends on I^2 R, and you can vary I by varying the duty cycle in the case of a buck converter.

Accordingly, reactance do not produce heat? (is that correct)?
https://www.allaboutcircuits.com/te...ent/chpt-11/true-reactive-and-apparent-power/
for heat, it is still the resistance within the inductor that produces it
if you have a superconducting coil, perhaps it can keep the magnet *on* perpetually without power dissipation.

 

When an inductor is saturated then its reactance is low and its resistance causes heating.
An inductor is usually used for its reactance with AC. An electromagnet can use DC but some use low frequency AC.