Electromagnets Flashcards
permanent magnet…
A permanent magnet is called a permanent magnet because its magnetism is ‘always on’, it generates its own persistent magnetic field and is always active.
non-permanent magnet…
known as temporary magnets
simply act like permanent magnets when they are within a strong magnetic field.
Unlike permanent magnets however, they loose their magnetism when the field disappears which can be controlled through current in an electromagnet. Paperclips, iron nails and other similar items are examples of temporary magnets.
An electromagnet is called a temporary magnet because it produces a magnetic field only when the current flows in its coil.
what is an electromagnet?
A non-permanent magnet turned on and off by controlling the current through it
solenoid…
Wire wound into a tight coil, part of an electromagnet.
In the diagram, the coil of insulated wire is the solenoid.
core…
Soft iron metal which the solenoid is wrapped around.
In the diagram, the iron nail is acting as the core.
DC…
DC or Direct Current is a situation where the current only flows in one direction at all times.
This is different from alternating current (AC) where the directions is continually changing.
armature…
A metal arm on a lever which is attracted to a magnet causing a circuit to connect or disconnect, e.g. in an electric bell
How does an electromagnet work?
Electromagnets are a different from permanent magnets.
Electromagnets are made of coils of wire with electricity passing through them. Moving charges create magnetic fields, so when the coils of wire in an electromagnet have an electric current passing through them, the coils behave like a magnet. When the electricity stops flowing, the coils don’t act like a magnet anymore. Electromagnets are used in a lot of electronic devices when magnetic forces are only needed for short periods of time.
