# Electromagnet design for 20Hz-20kHz AC

I am trying to design a U core electromagnet to pluck a ferromagnetic guitar string. The strings would sit at the outside center of the U core. I am wondering if high flux cores are ok for this application or if laminated electrical steel is ok for this frequency range. I seem to have concluded that powdered metal cores are the way to go at this frequencies to have somewhat high saturation margin and balanced eddy losses. It seems however that high flux cores exhibit soft saturation. The supplied signal would probably a damped sinewave and maybe other pulse profiles. Thelectromagnet should be powerful enough to apply the equivalent force of a finger plucking a guitar string. Did not look at impedance considerations yet.

• I think there are much easier ways to do what you want. I can't even begin to list the problems with this plan. – Hearth Jan 30 at 13:03
• You clearly have not modeled the physics of the situation well enough to even begin to think about implementation details at this level. This is just a bunch of vague ideas thrown together to see what sticks. For example, why on earth would an electromagnet simulating finger forces need a frequency response out to 20 kHz? Plucking a guitar string consists of pulling it to one side and then releasing it suddenly. How do you propose to do this with a magnetic field? How much field would you need? How much voltage will it take to stop the current in the required time? – Dave Tweed Jan 30 at 13:38
• Perhaps you want something more like this... :-) – Dave Tweed Jan 30 at 13:45
• I thpught that maybe if the stimulation pulse was a damped sinusoid at the resonant frequency of the string it may give an advantage of lower power required. It may not simulate properly a plucking action. In fact it is a bit experimental. I want to test all kinds of excitation signals – user3239774 Jan 30 at 14:01
• Focusing a huge EM field strength tightly enough for the force to "pluck" a guitar string is not impossible - theoretically - but not even close to feasible. Better to build a string plucker with a solenoid for about 0.001% the energy. – AnalogKid Jan 30 at 14:28