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Common Types of Transformer
Following are the few common types of transformer
Power Transformer - These power
transformers operate at 50 to 400 Hz at
a absolute nominal line voltage from 105 to 130 V. They
are actually made with single and multiple secondaries
with various step-up and step-down turns ratios.
Secondary Transformer - Secondaries
transformer could have a single tap, multiple taps and
even sometimes no tap. Some units are prepared with
a tapped primary. Output voltage could start ranging
from three to several thousand volts with output currents
from .01 to 1500 A.
The Cores Transformer - The cores
transformers are made up of iron or steel laminations.
They are packaged in a hermetically sealed case especially
for military or space use or with an open frame or even
plastic enclosure for commercial, consumer or any industrial
Isolation Transformer - These types
of transformer operate with a one-to-one turnís ratio
between primary and secondary, as isolating the line
from the secondary load. Usually, an isolation transformer
further comprises of Faraday shield, which is in fact
a screen of nonmagnetic metal wound between the primary
and secondary and then connected to the transformer
The Shield Transformer - The shield
transformer acts particularly to prevent capacitive
coupling of spurious signals and sound between windings,
and it as well reduces transformer efficiency by improving
Control Transformer - These are used
as small power transformer for controlling components
like relays and low voltage ac control devices. Common
output voltages come in 12 and 24 Vac at current capabilities
of 4 to16 A.
Autotransformer - Autotransformers
are types of single winding with either fixed or variable
step-up or step-down turnís rations. They are actually
smaller and less pricey than the two-winding types.
Audio Transformer - These audio
transformers vary from the power transformer
types in, which they are used to give matching electrical
characteristics of an output amplifier to that of any
normal load speaker. In high-fidelity audio systems,
they further operate from 20 Hz to 20 KHz. This audio
transformer comprises of voice communications only and
operates from 200 to 500 Hz.
Radio Frequency Transformer - These
radio frequency transformers operate at a fixed high
frequency with a capacitor across primary, secondary
or sometimes even both to create a tuned or resounding
circuit. Most types normally use an air core; however
some are made up of ferrite slug to allow any sort of
adjustment for inductance windings over a given range.
They are generally assembled in aluminum-shielded container
to reduce pickup or radiation of magnetic fields.
Pulse Transformer - These types are used for
the generation and transmission of square wave pulses
with emphasis on fast rise and fall times of the pulse
and high-frequency response. These transformers are
packaged in a miniature enclosure, 1/4 inch to 1/2 inch
in diameter, and use an air core.