Could some SPICE guru please help. I am trying to mofrl two parallel wires, each of diameter 'd' mm, of length 'l' mm , separated by 's' mm. These two inductors will have both self(each) and mutual inductance. They can be modelled in SPICE as two parallel inductors as follows: L0 START0 END0 L1 START1 END1 k0 L9 L1 0.99 where 'k0' is the coupling constant< So, now is the mutual inductance to be added to the circuit, Any hnts suggestions would be very helpful; Thanks in advance.

On Thursday, November 30, 2017 at 4:00:52 PM UTC+11, wrot e: The two inductances - L1 and L2 and the coupling constant in the third line define the mutual inductance. The transformer equation is V1 = L1.dI1/dt + M. dI2/dt V2 = M. dI1/dt + L2. dI2/dt For perfect coupling M^2 = L1.L2 and the coupling coefficient k is the extent to which M is less than the ge ometric mean of L1 and L2. The coupling coefficient has to less than one (t hough it can be very close to one) which is to say M^2= k^2. L1.L2 note that k can be either positive or negative, so it's magnitude is what's less than one. I hope this helps. I got introduced to the transformer equation after I'd b een using transformers for some years, and I found that it clarified my thi nking wonderfully. Introductory texts mostly avoid it - presumably on the S teven Hawking principle that every successive equation in a text halves the potential readership. -- Bill Sloman, Sydney

How to model mutial inductance in SPICE

Nov 30, 2017 21 Replies

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Jim Thompson 8 years ago

The "K" statement has been a _component_ in PSpice ever since I can remember.

GVALUE ??

...Jim Thompson

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Jeroen Belleman 8 years ago

They aren't even single-pin nets, they don't exist at all. This is one of those cases where the GUI is abstruse and things start to make sense only when you see the netlist. LTspice also has a few places like that.

Jeroen Belleman

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