Example of SPICE simulation of mutual inductances

The syntax for a mutual inductance is as follows:

In which K is the value of the coupling coefficient that determine the mutal inductance: M=K.sqrt(L1xL2). An example of a complete SPICE file for the circuit given below follows.


  1. SPICE always needs a reference node numbered 0. One can never leave any node floating. For that reason we have connected the two coils together to node 0 (or put a large resistor between it). As there is no current flowing through this section, the circuit will not change by connecting these nodes.

  2. SPICE does not allow to connect a voltage source in parallel with an inductor, as it thinks that the voltage source is short circuited. You can place a small resistor (ex. 0.001 Ohm) in series with the voltage source to overcome this problem.

Back to Spice Guidelines

Jan Van der Spiegel;
Created Sept. 30, 1995; Updated Feb. 8, 2007