Direct current

This can be produced from alternating current or
supplied as a direct output from a battery. Direct
current always flows in the same direction. In
the United States, direct current powers cranes
and other industrial equipment. The
abbreviation for direct current is “DC”.

Distribution Transformers

Transformers rated 500KVA and below are
usually referred to as distribution type.
Exceptions include current and potential and
other specialty transformers.

Diode

A device that passes current in one direction,
but blocks current in the reversed direction.

Dielectric

Insulator such as glass, rubber, plastic, etc. that
separates two electrical conductors in a
transformer or capacitor, for example.

di/dt

The rate of change in current versus a rate of
change in time. Line reactors and isolation
transformers can be used to provide the
impedance necessary to reduce the harmful
effects that unlimited current sources can have
on phase controlled rectifiers (SCRs).