|
Direct
current
is where
at all
times
the
voltage
polarity
remains
constant.
Unlike
a.c.
there is
no
varying
cycle.
D.C. may
however,
particularly
where it
is
rectified
from
mains
a.c.,
contain
residual
a.c.
superimposed
or part
of the
voltage.
This is
often
referred
to as
mains
hum.
Current
which
moves in
a single
direction
in a
steady
flow.
Normal
household
electricity
is
alternating
current
(AC)
which
repeatedly
reverses
its
direction.
However,
many
electronics
devices
require
DC, and
therefore
must
convert
the
current
into DC
before
using
it.
Diodes
are used
to
convert
AC to DC |
