Imagine an electromagnet. If you have a high current and low voltage vs a low current and high voltage which will create a stronger magnetic field? I understand the low current high voltage has to have a higher resistance but imagine it has a way of changing without changing the number of windings or anything else.
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The magnetic field is directly proportional to current. It is also directly proportional to voltage.
Due to this, neither current nor voltage can be said to be “more important” in terms of creating a stronger magnetic field.
https://physics.stackexchange.com/questions/90585/is-voltage-important-when-creating-a-magnetic-field
Magnetism is a function of current (amperage). The higher the current the stronger the magnet.
The strength of magnetic field depends entirely on current. In the idle state (when the magnet doesn’t actively attract or repel things), the voltage is parasitic – it is only used to fight with the resistance of the material. All consumed energy is wasted on heat – the magnetic field itself does not require “upkeep”. In superconductors, it is possible to have current with 0 voltage – so superconductor electromagnets do not require voltage or energy to keep a magnetic field up.
The things get different, when the things get moving in the magnetic field. When the magnet speeds up some object – it experiences **counter-electromotive force voltage (counter EMF)**. This voltage will act against the current, reducing it, as well as the strength of the field. You have to actively *increase* the voltage, if you want to keep the strength the same. Even superconductor electromagnets will require a voltage in this case – therefore, they will consume energy.
When the electromagnet slows down things, it experiences the opposite effect – **forward EMF**. The magnet will become a source of voltage – you can connect it to the grid, and it will generate electricity.
Maxwell’s equations fundamentally define the properties of electromagnetic fields, and voltage isn’t a factor here. Current (specifically current density) is the main input into this equation. (Note: Ignoring polarization current for this discussion, which muddies the waters a little bit)
The premise of your question is what is misguiding the discussion a little bit. All other things held equal, a conductor with high current and low voltage applied across it will produce the strongest magnetic field.
You alluded to it a little bit, but increasing the number of turns in a current loop will produce a stronger magnetic field. This is one of the reasons why it is most useful for Maxwell’s equations to express current as current density (coulombs per second per square meter) rather than just current (coulombs per second). Even if we hold the current equal, increasing the number of turns in a winding increases the current density.
Source: Electrical Engineer / Electromagnetic transient simulation
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