Aircraft Electronics Technician AET - NCATT

NCATT Aircraft Electronics Technician (AET) Study Guide
• Shorted Capacitors
o Conductive surfaces (plates) come into physical contact with each other
o Electrical qualities of the capacitor no longer exist
12. Transformer / Theory of Operation
NCATT Level B
Outcome: A successful education or training outcome for this task/subject will produce an
individual who knows and can identify the relationship of basic facts and state general principles
about “Transformer Theory of Operation”. The following is a minimum list of terms associated
with this subject.
Theory of Operation:
• Counter EMF
o See Basic Terms/Direct Current (DC)
• Eddy Current
o Current loss due to heating of the core that alters the overall distribution of current
flowing through the conductor
o As the current flows, the core heats up and resistance increases due to the core
positive temperature coefficient
• Hysteresis
o Current loss due to a lag between the physical action occurring and the cause of
loss
• Primary Winding
o Input winding of a transformer connected across a power line
• Secondary Winding
o Winding of a transformer that supplies energy to the load device
• Step-down
o Decreases the voltage and increases the current
o Step-down transformers have more turns in the primary coil than in the secondary
coil, or winding
• Step-up
o Increases the voltage and decreases the current
o Step-up transformers have more turns in the secondary coil than the primary coil,
or winding
Transformer classifications:
• Frequency range
• Power application
• Winding style
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