I am trying to simulate a circuit that involves pickup coils in Spice. How would one simulate the magnetic fields that the pickup coils can sense? Additionally, how would one get a frequency response for such an input? (By frequency response, I mean output voltage vs input flux)

One idea I thought of is using a magnetic coupling (K) between the simulated coil and another "input" coil through which a known current can be passed. The current in the "input" coil would cause a current to flow through the simulated coil due to the coupling, and essentially simulate a field causing a current flow. The issue with this problem is that I am unable to get an output voltage frequency response based on the input current (I'm using MultiSim).

Any ideas?

  • \$\begingroup\$ I know this is old, but it sounds like your issue is that you're not using a time varying signal on the magnetically coupled "input" coil. A constant current won't result in any response on the pickup coil using this model. Am I misunderstanding your question? \$\endgroup\$
    – horta
    May 12, 2014 at 20:35
  • \$\begingroup\$ You might consider modelling it as an air core transformer \$\endgroup\$
    – user32885
    May 22, 2014 at 8:32

1 Answer 1


Model the change in field as a single ac voltage source. Add to this a resistance and inductance (pickup winding resistance and leakage inductance). For even better accuracy add some capacitance to model a bulk interwinding capacitance:

Lleakage 1 N1 <value>

Vac 2 N2 <func_of_time>

Rwinding 2 1  <value>

Cparasitic N1 N2 <value>

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