The transient response refers to the initial behavior of the circuit right after a change, such as when a switch is turned on or off. It includes the momentary changes in current and voltage before the system stabilizes.
What is the steady-state response of a circuit?
A Energy storage
B Voltage variation
C Final, stable condition
D The initial change
The steady-state response refers to the behavior of a circuit after a long period when it has settled into a stable state. All transient effects have dissipated, and the current/voltage values remain constant.
What type of current does an AC circuit use?
A Alternating
B Steady
C Pulsed
D Unidirectional
An AC circuit uses alternating current, where the flow of electrons changes direction periodically. This type of current is used in most power distribution systems due to its efficient transmission over long distances.
What happens when a capacitor is connected to a DC voltage source?
A Does not react
B Discharges immediately
C Charges up
D Constant current
When a capacitor is connected to a DC voltage source, it charges up to the applied voltage. After reaching full charge, it behaves like an open circuit, and no more current flows through it.
How does increasing frequency affect inductive reactance in an AC circuit?
A Increases
B No change
C Becomes zero
D Decreases
Inductive reactance is directly proportional to the frequency of the AC signal. As the frequency increases, the inductive reactance increases, which opposes the flow of current more strongly in the circuit.
What is the effect of a resistor in an AC circuit?
A Voltage increase
B Phase shift
C Current increase
D Energy dissipation
A resistor in an AC circuit dissipates energy as heat. It does not store energy but instead converts electrical energy into heat, thus reducing the total available energy for other components in the circuit.
What is the characteristic of an underdamped response in a circuit?
A Stable voltage
B Slow decay
C Fast decay
D No oscillation
An underdamped response occurs when the circuit’s oscillations slowly decay over time, typically in RLC circuits. It happens when the damping is insufficient to eliminate oscillations quickly, resulting in a gradual decrease in amplitude.
How is total impedance calculated in a series RLC circuit?
A Difference between reactances
B Root sum square
C Sum of reactances
D Sum of individual resistances
In a series RLC circuit, the total impedance is calculated by taking the square root of the sum of the squares of the resistance and the reactances (both inductive and capacitive). This gives the overall opposition to current.
What does a low power factor indicate?
A High energy loss
B Maximum energy transfer
C Efficient power usage
D Voltage drop
A low power factor indicates that a large portion of the energy is being wasted. This is often due to phase differences between voltage and current, causing inefficiency in power usage and increased energy losses.
What is the effect of resonance in a parallel RLC circuit?
A No current
B Maximum voltage
C Maximum current
D Minimum current
At resonance in a parallel RLC circuit, the impedance becomes minimum, allowing maximum current to flow through the circuit. This is because the inductive and capacitive reactances cancel each other out, creating a purely resistive circuit.
What does the Laplace transform help with in circuit analysis?
A Voltage division
B Time-domain behavior
C Impedance calculation
D Frequency-domain analysis
The Laplace transform converts time–domain functions into the frequency domain, making it easier to analyze complex circuits, especially when dealing with transient responses. It helps solve differential equations in circuit analysis.
How is the total current in a parallel circuit related to individual branch currents?
A Equal to sum of currents
B Same as branch currents
C Inversely proportional
D Zero total current
In a parallel circuit, the total current is the sum of the individual currents in each branch. This is due to the multiple paths for current flow, where the current divides according to the branch resistances.
What does the term ‘impedance’ refer to in an AC circuit?
A Only reactance
B Resistance to DC
C Total opposition to current
D Only resistance
Impedance in an AC circuit refers to the total opposition to current, which includes both resistance and reactance (inductive and capacitive). It is a complex quantity that affects the current flow in AC circuits.
What is the relationship between voltage and current in a purely resistive AC circuit?
A 180 degrees out of phase
B In phase
C 90 degrees out of phase
D Not related
In a purely resistive AC circuit, the voltage and current are in phase with each other. This means that the voltage and current reach their maximum and zero values simultaneously, resulting in no phase shift between them.
What is the primary function of a transformer in AC circuits?
A Increase current
B Store energy
C Change voltage levels
D Convert DC to AC
A transformer is used in AC circuits to change the voltage level. It works on the principle of electromagnetic induction to step up or step down the voltage while maintaining the power (neglecting losses).