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DC Electric transformers
between AC and DC Electric transformers
As most of us are aware, electricity
flows in two ways - either as alternating
current (AC) or as direct current (DC).
Electric current can be described as the moving electrons
along a conductor, like a wire, that have been harnessed
for energy. Therefore, simply stated, the difference
between AC and DC is the direction in which the electrons
flow. In DC, the electrons flow steadily in a single
direction that is forward. In AC, electrons keep switching
directions, sometimes going forwards and then going
backwards. The power that comes from our wall outlets,
at the various buildings including our homes, is the
more common AC.
Now, alternating voltage is carried
around the country in cables far more efficiently than
direct current where the voltage is fixed. So the electricity
that arrives at our house is still alternating voltage.
Electric light bulbs and fires can run on 230 volt AC.
Other equipment such as televisions has an internal
power supply which converts the 230 volts AC to a low
DC voltage that is safe and acceptable to the electronic
the search to create electrical energy, scientists discovered
that electrical and magnetic fields are related. A magnetic
field near a wire causes electrons to flow in a single
direction along the wire because they are repelled and
attracted by the north or south poles. Thus, DC power
from a battery was born. Another scientist, Nikola Tesla,
preferred AC because it travels farther without losing
energy and could transfer different amounts of power.
Instead of applying the magnetism along the wire steadily,
he used a magnet that was rotating. When the magnet
was oriented in one direction, the electrons flowed
towards the positive, but when the magnet's orientation
was flipped, the electrons turned as well. AC generators
gradually replaced DC battery system as AC was found
safer to transfer over the longer distances and provided
The AC's voltage from a generator,
in a power plant, can be pushed up or down in strength
by another device called a transformer. Transformers
are ubiquitously found on the electrical pole at street
corners. They change very high voltage into a lower
voltage appropriate for your home appliances, like lamps
and refrigerators. AC can even be reverted to DC by
an adaptor that you might use to power the battery on
As we know, electrical
transformers are used to transform voltage
from one level to another, usually from a higher voltage
to a lower voltage. This is done by applying the principle
of magnetic induction between coils to convert voltage
and/or current levels. A transformer combines several
major characteristics of electricity and magnetism to
change AC voltages. DC transformers are now available,
but they won't replace AC transformers.
You can see that DC voltages could
not be changed with the configuration of the transformer.
This is because the DC current would not be changing
the magnetic field in the manner AC current does. And
this was the reason that AC scored over DC when electricity
started to be used around the world. Since then, electrical
engineers have developed DC transformers, primarily
using special circuitry. Since everyone now uses AC,
it is too late to change to DC system.