please dont rip this site

Component: Inductors

Testing: Setup a simple switching circuit with a MOSFET to ground, an inductor, and a freewheel diode. Then generate a narrow pulse at some arbitrary rate of change (you will understand quickly as you begin to look). Put a low ohm resistor in the ground below the FET so that you can look at the current. Add an IA to get out of the noise. When you pulse the fet, the current will ramp up as a triangle. If you work out the applied voltage and the DI/DT, then you can figure out the inductance fairly easily. V=1/2L(DI/DT). Then you widen the pulse width (generate it with a saw and a comparator so that you can vary the duty, unless you own a cool wave gen). At some point, you will see the current flatten out. This is generally the current saturation level of the core material. You will rarely find it roll over at a single point, it just kind of curves over.

It works on power inductors and transformers, too. On transformers, leave all secondaries disconnected.

Richard Prosser says

As the inductor goes into saturation, the inductance decreases - therefore di/dt increases. The flattening of the display is more likely due to the resistance in the circuit limiting the maximum. The droop you note is probably due to the FET resistance increasing as it warms up - thereby7 reducing the current. (I'm assuming the FET Rds is >> coil resistance & the dc supply is OK for the peak current)

Measureing inductance

Magnetic Amplifiers: Controlling high current AC with DC signal

Stepper Motor Inductance / Torque

Ferrite Bead

Inductors act like a large resistor at higher frequencies, but a small resistor at DC. XL is inductive reactance [similar to "impedance"]:

XL = 2*PI*f*L

For example a 10 uH inductor will act like a resistor of 63 ohms @ 1 Mhz and 630 ohms @ 10 Mhz.

book Introduction to Microwave Engineering"

See also (thanks to M. Adam Davis)



See also:

file: /Techref/inductor.htm, 11KB, , updated: 2020/12/18 06:35, local time: 2024/6/16 07:48,

 ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it! / MAKE!

<A HREF=""> Inductors, Windings, Ferrite, MagAmp</A>

After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type a nice message (short messages are blocked as spam) in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.

Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?


Welcome to!

Site supported by
sales, advertizing,
& kind contributors
just like you!

Please don't rip/copy
(here's why

Copies of the site on CD
are available at minimal cost.

Welcome to!