30 Questions
What happens when a magnet is suspended to swing freely?
It aligns itself with the earth's magnetic poles
What is the function of the magnetic field surrounding a magnet?
It arranges itself to conform to the shape of the magnet
What is the primary principle behind the generation of AC voltage in a generator?
A conductor passing through lines of magnetic force
What determines the strength of the induced voltage in a generator?
The speed of the conductor and the strength of the magnetic field
What is the purpose of labeling the ends of a magnet as 'N' and 'S'?
To distinguish the north-seeking and south-seeking ends of the magnet
What is the earth's role in the behavior of magnets?
It is a giant magnet, with its poles attracting the ends of other magnets
What is a characteristic of a shunt DC motor?
Constant current through the field
Which type of DC motor is suitable for applications where constant speed is desired and high starting torque is not needed?
Shunt motor
What is the primary difference between a shunt and a series DC motor?
The connection of the field winding to the armature
What is the purpose of the series winding in a compound DC motor?
To provide a high starting torque
What is the characteristic of a compound DC motor's speed with load?
It varies less than in a series wound motor
What is the number of windings in the field of a compound DC motor?
Two
What is the relationship between the effective value and the peak value of an AC circuit?
The effective value is equal to 0.707 times the peak value.
Why are AC meters typically calibrated to display the effective value?
Because it is the approximate DC voltage of the same value.
What is the assumption made when a value is given for current or voltage in an AC circuit?
The value is always the effective value unless otherwise specified.
What is the purpose of specifying the effective value in AC circuits?
To provide a practical and useful measurement for AC circuits.
What is the relationship between the effective value and the heat produced in a resistor?
The effective value produces the same heat as the peak value.
What is the term used to describe the mathematical process of deriving the effective value?
Root mean square (RMS) value.
What is the primary purpose of a voltage transformer?
To step up or step down voltages
What is the primary difference between the primary windings of voltage and current transformers?
The connection method in the primary circuit
What is the name of the law that describes the current flow in the primary coil when voltage is applied?
Faraday's Law of Electromagnetic Induction
What is the primary function of the soft iron core in a transformer?
To form a path and concentrate the magnetic flux
What determines the strength of the magnetic field induced in a transformer?
The amount of current and number of turns in the winding
What is the name of the phenomenon that occurs when a current flows through the primary coil and sets up a magnetic field?
Mutual inductance
What is the characteristic of semiconductor materials?
Offering a resistance between the best conductors and insulators
Which of the following is a poor conductor of electricity?
Rubber
What is the relationship between the length of a wire and its resistance?
The longer the length, the greater the resistance
What happens to the resistance of a conductor when its cross-sectional area is doubled?
The resistance is reduced in half
What is the effect of temperature on the resistance of most conductors?
The resistance increases as temperature increases
Why does the resistance of a conductor decrease when its cross-sectional area is increased?
The electrons move without collision in the increased area
Learn about the fundamentals of transformers in aircraft electrical systems, including voltage transformers and current transformers. Understand how primary coils are connected in parallel across the supply voltage and their applications in instrument circuits.
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