Introduction to Transformers Flashcards
The purpose of a transformer is to _______.
The purpose of a transformer is to transfer power.
With transformers, POWER IN always equal_____
POWER IN = POWER OUT
The input to a transformer is applied to one coil called the _____.
The input to a transformer is applied to one coil called the primary.
The output of a transformer is taken from the other coil, which is called a_______.
The output of a transformer is taken from the other coil, which is called a secondary.
The reference designation for a transformer is the letter ____
The reference designation for a transformer is the letter T
Transformers T1, T4, T5, and T6 have iron cores. Iron core transformers are used mostly in ______.
Transformers T2 and T3 have air cores. Air core transformers are often used in _______.
Transformers T1, T4, T5, and T6 have iron cores. Iron core transformers are used mostly in power supplies.
Transformers T2 and T3 have air cores. Air core transformers are often used in radio circuits.
Both iron core and air core variable transformers are used in ________.
Both iron core and air core variable transformers are used in radio circuits.
Transformers operate on the principle of mutual inductance.
What is mutual inductance?
Mutual inductance is the ability of the magnetic field of one coil to induce voltage in a second coil.
AC current causes the magnetic field to expand and contract at a rate equal to the input frequency. What happens if a second coil is placed next to the first coil?
AC current causes the magnetic field to expand and contract at a rate equal to the input frequency. Placing a second coil next to the first coil allows the expanding and contracting magnetic field to induce voltage in the second coil.
Es depends on Ep, Np, and Ns:
Es - ______
Ep - ______
Np - ______
Ns - ______
Es depends on Ep, Np, and Ns:
Es - secondary voltage
Ep - primary voltage
Np - number of turns in primary
Ns - number of turns in secondary
If __ is lower than __, the transformer STEPS DOWN the voltage.
If Es is lower than Ep, the transformer STEPS DOWN the voltage.
Step up transformers producea a higher ____ than ____
a higher Es than Ep
Transformers do not change the frequency of the applied AC or sine wave signal. Transformers can, however, reverse the phase of the applied AC voltage or sine wave. This is called______.
Transformers do not change the frequency of the applied AC or sine wave signal. Transformers can, however, reverse the phase of the applied AC voltage or sine wave. This is called phase inversion.
Phase inversion occurs when the primary and secondary coils of a transformer are wound in opposite directions around the core. These types of transformers are called ______.
Unlike-wound transformers.
When the primary and secondary coils of a transformer are wound in the same direction around the core, there is no phase inversion. These types of transformers are called _____
Like-wound transformers
What is a turn ratio?
What is it used for?
Turns ratio compares the number of turns in the primary to the number of turns in the secondary.
The turns ratio is used to calculate secondary voltage and primary current.
EX: A transformer with a 1:10 turns ratio and a primary input of 120 volts has a secondary voltage of _____.
a transformer with a 1:10 turns ratio and a primary input of 120 volts has a secondary voltage of 1,200 volts.
EX: A transformer with a 5:1 turns ratio and a primary input of 120 volts has a secondary voltage of ____.
A transformer with a 5:1 turns ratio and a primary input of 120 volts has a secondary voltage of 24 volts.
