Podcast
Questions and Answers
What happens to the voltage across an inductor when the current through it is constant (DC circuit)?
What happens to the voltage across an inductor when the current through it is constant (DC circuit)?
- The voltage fluctuates randomly.
- The voltage increases linearly with time.
- The voltage is zero. (correct)
- The voltage is equal to the current multiplied by the inductance.
What is the nature of an inductor as a circuit element?
What is the nature of an inductor as a circuit element?
- An active, reactive element that generates power.
- A passive, reactive element that stores magnetic energy. (correct)
- A passive element that dissipates power.
- An active element that dissipates power.
In a system of two coupled inductors, which of the following best describes the relationship between their voltages and currents?
In a system of two coupled inductors, which of the following best describes the relationship between their voltages and currents?
- The voltage across one inductor only depends on the absolute value of the current through both inductors.
- The voltage across each inductor depends only on the current through itself.
- The voltage across one inductor depends on the rate of change of current through both inductors. (correct)
- The voltage across each inductor depends only on the current through the other inductor.
What does it mean when inductors are 'coupled'?
What does it mean when inductors are 'coupled'?
What does the symbol 'M' represent in the context of two coupled inductors?
What does the symbol 'M' represent in the context of two coupled inductors?
What is a key characteristic of a circuit in a 'variable state'?
What is a key characteristic of a circuit in a 'variable state'?
What is the relationship between the current through a capacitor and the voltage across it?
What is the relationship between the current through a capacitor and the voltage across it?
What units are used to quantify capacitance?
What units are used to quantify capacitance?
What is the behavior of the capacitor in a DC circuit (when the voltage is constant)?
What is the behavior of the capacitor in a DC circuit (when the voltage is constant)?
Which of the following is NOT a characteristic of the voltage across a capacitor?
Which of the following is NOT a characteristic of the voltage across a capacitor?
What is the fundamental characteristic of an inductor, as described in the text?
What is the fundamental characteristic of an inductor, as described in the text?
In what units is inductance measured?
In what units is inductance measured?
Which statement is true regarding the current flowing through an inductor, as described in the text?
Which statement is true regarding the current flowing through an inductor, as described in the text?
Flashcards
Capacitor
Capacitor
A circuit element where the current is directly proportional to the rate of change of voltage across it.
Capacitance
Capacitance
The ability of a capacitor to store electrical energy, measured in Farads (F).
Capacitor in DC Circuit
Capacitor in DC Circuit
The current through a capacitor is zero when the voltage across it is constant.
Inductor
Inductor
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Inductance
Inductance
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Inductor in DC Circuit
Inductor in DC Circuit
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Inductor Equation (Receiver Convention)
Inductor Equation (Receiver Convention)
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Inductor Equation (Generator Convention)
Inductor Equation (Generator Convention)
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Magnetic Energy Stored by Inductor
Magnetic Energy Stored by Inductor
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Coupled Inductors
Coupled Inductors
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Mutual Inductance
Mutual Inductance
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Ideal Voltage Source
Ideal Voltage Source
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Study Notes
Electrical Engineering 1 - EE1
- Course name: Fundamentals of Electrical Engineering 1 - FEE1
- Course notes by: Assoc. Prof. PhD. Eng. Mihai Iulian REBICAN
- Course years: 2024-2025
Electric Circuits in Variable State
- Variable state circuits: Current and voltage in elements are not constant over time. Variations include sinusoidal, exponential, step, and more.
- First Kirchhoff's Theorem: The sum of currents entering a node equals zero. Σ 𝑖(𝑘)(𝑡) = 0
- Second Kirchhoff's Theorem: The sum of voltages around a closed loop equals zero. Σ 𝑣(𝑘)(𝑡) = 0
- Power of a one-port element: p(t) = u(t)⋅i(t)
Ideal Passive Circuit Elements
Resistor
- Equation: u(t) = R⋅i(t)
- Power: p(t) = R⋅i²(t)
Capacitor
- Equation: i(t) = C(du(t)/dt) (for receiver convention) or i(t) = -C(du(t)/dt) (for generator convention)
- Voltage across capacitor: u(t) = (1/C)∫i(t)dt + u(t₀)
- Capacitor is a symmetric element
- In DC circuits, capacitor acts as an open circuit.
Inductor
- Equation: u(t) = L(di(t)/dt) (for receiver convention) or u(t) = -L(di(t)/dt) (for generator convention)
- Current through inductor: i(t) = (1/L)∫u(t)dt + i(t₀)
- Inductor is a symmetric element
- In DC circuits, inductor acts as a short circuit.
Energetic Characterization
- Capacitor: Electric energy stored: Wₑ = (1/2)C⋅u²(t)
- Inductor: Magnetic energy stored: Wₘ = (1/2)L⋅i²(t)
Coupled Inductors
- Mutual inductance: Exists between two or more inductors if a changing current in one of them creates a changing magnetic field which influences the current in another.
- Energy: Wₘ=½Lᵢᵢ₁² + ½L₂ᵢ₂² + Mᵢ₁ᵢ₂
- Coupling coefficient (k): a measure of the degree of magnetic coupling
- Perfect coupling (k=1): |M| = √(L₁L₂)
- No coupling (M=0): Inductors are independent.
Ideal Active Circuit Elements
- Ideal voltage source: u(t) = ±e(t)
- Ideal current source: i(t) = ±j(t)
Real Branches
- Combinations of ideal components like resistors, inductors, capacitors, voltage and current sources.
- Equations become more complex to include initial state effects.
Real Branches with Magnetic Coupling Inductors
- Includes the equations for handling magnetic coupling.
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