An external electronic control type electrodeless lamp includes a lighting
device. The lighting device includes a body having at least a first
conductive plate and a second conductive plate. Each conductive plate is
electrically connected to an electronic control system external to the
lighting device. The body has a plurality of even-numbered sides. The
number of the sides of the body is at least four. The conductive plates
are mounted on at least two opposite sides of the body. The electronic
control system includes a magnetic core that, when energized, creates a
magnetic field, and current generated due to change in the magnetic field
is supplied to the conductive plates to light the lighting device.