O-core transformer as a special transformer wound from a continuous
silicon steel strip. It is wound into circular shape which is
similar to toroidal transformer. What is more , O-core transformer
resembles R-core transformer having a circular cross section, which
is different to rectangular cross section of toroidal transformer.
For there are no sharp corners, the coils can be wound at much
lower tension and will reduce the distributed capacitance between
the windings and increase the uniformity of magnetic field. So
audio amplifiers and other noise sensitive equipment all benefit
from the excellent performances of O-core transformer.