What is the purpose of power factor correction in an electrical system?
A To reduce the total voltage
B To reduce energy losses by aligning the phase of current and voltage
C To store excess energy in capacitors
D To convert AC to DC
Power factor correction aims to improve the efficiency of power usage by reducing the phase difference between the current and voltage waveforms, minimizing reactive power and reducing energy losses.
Which of the following is an example of a passive component in an electrical circuit?
A Diode
B Transistor
C Resistor
D Integrated Circuit
A resistor is a passive component because it dissipates energy as heat and does not amplify or generate energy like active components such as transistors.
What is the main characteristic of active components?
A They store energy
B They amplify or switch signals
C They do not consume power
D They only resist current flow
Active components like transistors can amplify signals or switch electronic signals, enabling them to control current flow in the circuit.
What is the role of feedback in an electronic amplifier circuit?
A To regulate the voltage
B To stabilize the circuit and reduce distortion
C To store energy
D To increase current
Feedback in amplifiers is used to stabilize and control the output by reducing distortion, ensuring consistent performance.
What is the purpose of electrical filters in a circuit?
A To allow only a single frequency to pass while blocking others
B To store electrical energy
C To convert AC to DC
D To increase the current
Electrical filters are used to allow certain frequencies to pass through while blocking unwanted frequencies, which is crucial for signal processing and communication systems.
What does an equivalent circuit represent?
A A model that simplifies the analysis of a circuit
B A circuit with infinite resistance
C A circuit with only passive components
D A series combination of all components
An **equivalent circuit** is a simplified version of a more complex circuit. It uses basic components to represent the behavior of the original circuit and makes it easier to analyze.
What is energy transfer in an electrical circuit?
A The storage of energy in capacitors and inductors
B The process of moving energy from the source to the load
C The conversion of electrical energy into mechanical energy
D The dissipation of energy as heat
**Energy transfer** refers to the movement of electrical energy from the power source to the load, where it is either used or stored for later use.
What is the role of digital circuits in electronics?
A To process signals in continuous values
B To process signals in discrete binary values (0 and 1)
C To store energy in inductive components
D To regulate power usage in the circuit
**Digital circuits** process signals represented by discrete binary values, commonly used in computers, logic gates, and digital electronics.
What is the main objective of circuit design techniques?
A To increase the power consumption of the circuit
B To make the circuit as simple as possible without compromising performance
C To store energy efficiently
D To decrease the impedance of the circuit
The goal of **circuit design techniques** is to create efficient circuits that meet performance requirements while keeping the design as simple as possible.
In a series circuit, what happens when additional resistors are added?
A The total resistance decreases
B The total resistance increases
C The voltage across each resistor remains the same
D The total current decreases
In a **series circuit**, the total resistance increases as more resistors are added, because the resistances simply add up.
What happens to the impedance in a purely capacitive AC circuit as the frequency increases?
A It increases
B It decreases
C It remains constant
D It becomes zero
In a **purely capacitive AC circuit**, **capacitive reactance (XC)** decreases as the frequency increases, because **XC = 1 / (2πfC)**.
What is the phase shift between the current and voltage in a purely resistive AC circuit?
A 90 degrees
B 0 degrees
C 180 degrees
D 45 degrees
In a **purely resistive AC circuit**, the **current and voltage are in phase**, meaning they reach their maximum and minimum values at the same time, resulting in a **0-degree phase shift**.
What is the cutoff frequency in an electrical filter?
A The frequency at which the filter begins to attenuate the signal
B The frequency at which the impedance is zero
C The maximum frequency the filter can pass
D The frequency at which power is minimized
The **cutoff frequency** is the point at which a filter begins to reduce or block certain frequencies, depending on the type of filter.
What does power factor correction do to improve the efficiency of an electrical system?
A It minimizes the impedance of the circuit
B It aligns the phase between voltage and current
C It stores excess power in capacitors
D It increases the supply voltage
**Power factor correction** reduces the phase difference between current and voltage, making the system more efficient by ensuring more real power is used for work.
What is the main function of transistors in electrical circuits?
A To store energy
B To amplify or switch electronic signals
C To regulate power supply
D To control the frequency of signals
**Transistors** are used to amplify signals or act as switches, enabling them to control the flow of current in various types of circuits.
What happens when a capacitor is placed in series with a resistor in an AC circuit?
A The current becomes zero
B The capacitor blocks DC while allowing AC to pass
C The capacitor stores all the energy
D The voltage across the resistor and capacitor is equal
When a capacitor is placed in series with a resistor in an AC circuit, it allows **AC signals** to pass through while blocking **DC signals** after the capacitor is fully charged.
In a parallel circuit, what happens when resistors are added?
A The total resistance decreases
B The total resistance increases
C The total voltage decreases
D The current becomes zero
In a **parallel circuit**, adding more resistors provides additional paths for current to flow, which reduces the total resistance of the circuit.
What is the primary purpose of diodes in circuits?
A To store electrical energy
B To allow current to flow in only one direction
C To resist current flow
D To amplify signals
**Diodes** are semiconductor devices that allow current to flow in only one direction, which makes them essential in rectifying circuits, converting AC to DC.
How does resonance affect the impedance in a series RLC circuit?
A It increases the impedance
B It decreases the impedance to a minimum value
C It causes the current to be zero
D It increases the voltage
At **resonance** in a series **RLC circuit**, the **inductive reactance (XL)** and **capacitive reactance (XC)** cancel each other out, resulting in the minimum impedance and maximum current.
What does an inductor store in an AC circuit?
A Energy in the form of an electric field
B Energy in the form of a magnetic field
C Energy in the form of a resistive element
D Energy in the form of a capacitive element
An **inductor** stores energy in the form of a **magnetic field** when current flows through it. This stored energy can be released when the current changes.