What do the coils do?

As electricity flows through the
tattoo machine it travels around
the coils in the wire, creating an
electro-magnetized core. It is this
magnet that will pull down on the
armature bar and force the needle
into the skin. When the armature
bar is pulled down, the front
spring that is attached to it loses
contact with the front binding
contact screw. When the contact
screw loses contact with the front
spring, the electrical circuit is turned off. While the circuit is off,
there is no electricity flowing through the coils (or a very limited
amount); causing the armature bar to be released from the magnetic
field pulling it down. This obviously will remove the needle
from the skin and complete the cycle.