What is the primary function of a transformer in a circuit?
A Voltage conversion
B Current conversion
C Power factor correction
D Energy storage
A transformer is used to change the voltage level in AC circuits. It can step up or step down the voltage depending on the number of turns in the primary and secondary coils, making it essential for efficient power transmission.
How does circuit simplification affect the analysis of complex circuits?
A Increases complexity
B Reduces calculation errors
C Decreases component count
D Removes components
Circuit simplification involves reducing complex networks of components into simpler equivalent circuits. This helps to easily calculate voltages, currents, and other parameters, reducing errors and improving accuracy in analysis.
What is power factor correction used for in electrical systems?
A Increase current flow
B Improve circuit resistance
C Decrease energy loss
D Improve voltage regulation
Power factor correction aims to reduce the phase difference between voltage and current, improving the efficiency of power usage in electrical systems. By correcting the power factor, energy losses due to reactive power are minimized.
What is the key principle of a transformer’s operation?
A Faraday’s law
B Direct current
C Capacitive reactance
D Mutual induction
A transformer works on the principle of mutual induction, where a changing current in the primary coil induces a current in the secondary coil. This process allows the transformer to either step up or step down voltage levels.
What is the effect of adding resistors in parallel on total resistance?
A Decreases
B Increases
C No effect
D Doubles
When resistors are added in parallel, the total resistance decreases. This is because the current has multiple paths to flow through, which reduces the overall opposition to the current.
What does an ideal transformer assume regarding power loss?
A Maximum loss
B Zero loss
C Power fluctuation
D Energy loss
An ideal transformer assumes that there are no power losses in the system, meaning that all the power input into the primary coil is transferred to the secondary coil without any energy dissipation or losses.
How is the efficiency of a transformer determined?
A Voltage ratio
B Current ratio
C Power output / Power input
D Impedance ratio
The efficiency of a transformer is determined by the ratio of power output to power input. Ideally, an efficient transformer has minimal losses, with most of the power delivered to the secondary coil.
What happens when you increase the power factor in an electrical system?
A Decreases efficiency
B Increases current
C Reduces voltage
D Reduces power loss
Increasing the power factor reduces the amount of reactive power in the system. This helps minimize energy losses and improves the overall efficiency of the electrical system by making better use of the supplied power.
What does the core of a transformer do?
A Provides a magnetic path
B Directs current
C Generates electricity
D Stores energy
The core of a transformer provides a path for the magnetic flux that is generated by the current in the primary coil. This magnetic flux is then transferred to the secondary coil, enabling the voltage transformation.
What is the relationship between the primary and secondary windings in an ideal transformer?
A Inverse
B Direct
C Unrelated
D Independent
In an ideal transformer, the relationship between the primary and secondary windings is direct, determined by the ratio of turns in each coil. The voltage ratio is proportional to the turn ratio of the coils.
What happens to the total current in a parallel circuit when more branches are added?
A Stays constant
B Decreases
C Increases
D Fluctuates
In a parallel circuit, as more branches are added, the total current increases. This is because each new branch provides an additional path for current to flow through, effectively lowering the total resistance and increasing current.
How does power factor correction improve an AC system?
A Reduces voltage
B Reduces impedance
C Increases efficiency
D Decreases frequency
Power factor correction improves the efficiency of an AC system by reducing the phase difference between voltage and current. This results in more effective power usage, lowering losses and improving the system’s overall performance.
How does adding capacitors in parallel to a load affect the power factor?
A Increases lead
B Increases lag
C Decreases power factor
D Stabilizes voltage
Adding capacitors in parallel to a load helps correct the power factor by causing the current to lead the voltage. This reduces the overall phase difference, improving the power factor and increasing system efficiency.
What is the role of the primary coil in a transformer?
A Supplies power to the system
B Induces current in the secondary coil
C Stores energy
D Regulates voltage
The primary coil in a transformer creates a magnetic field when current passes through it. This magnetic field induces a current in the secondary coil, leading to a change in voltage according to the turns ratio of the coils.
What happens to the impedance in a parallel circuit with capacitors and resistors?
A Increases
B Decreases
C Remains constant
D Fluctuates
In a parallel circuit with capacitors and resistors, the total impedance decreases as more capacitive elements are added. Capacitors provide an alternative path for current, which reduces the overall impedance and increases current flow.