A.C. Fundamentals - Purely Inductive Circuit
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A.C. (alternating current) fundamentals include the study of various electrical circuits and components that operate with alternating current. A purely inductive circuit is one type of circuit that is primarily composed of inductive elements.
An inductor is a passive electrical component that stores energy in its magnetic field when current flows through it. It opposes any changes in the current passing through it. In a purely inductive circuit, the only component present is an inductor, and there are no resistors or capacitors in the circuit.
Key characteristics of a purely inductive circuit:
Phase Relationship: In a purely inductive circuit, the current lags the voltage by 90 degrees. This means that the current reaches its maximum value a quarter of a cycle (90 degrees) after the voltage reaches its maximum value. The voltage across the inductor leads the current by 90 degrees.
Voltage and Current Relationship: In a purely inductive circuit, the voltage across the inductor is directly proportional to the rate of change of current with respect to time. Mathematically, this can be expressed as: V = L di/dt, where V is the voltage across the inductor, L is the inductance of the coil, and di/dt is the rate of change of current.
Impedance: Impedance in an AC circuit is similar to resistance in a DC circuit. For a purely inductive circuit, the impedance (Z) is equal to the inductive reactance (XL), which is given by XL = 2πfL, where f is the frequency of the AC signal and L is the inductance of the coil.
Resonance: Purely inductive circuits are often encountered in the analysis of resonant circuits, particularly in series resonance. At resonance, the inductive reactance cancels out the capacitive reactance (if present) resulting in a higher current flow through the circuit.
Power Factor: In a purely inductive circuit, the power factor is lagging, and the apparent power (S) is equal to the reactive power (Q), with no real power (P) being consumed. This means that the energy oscillates between the source and the inductor without being dissipated as heat.
It's important to note that in real-world scenarios, purely inductive circuits are relatively rare because most circuits contain a combination of inductance, resistance, and capacitance. These components interact to create a variety of circuit behaviors, and their study is essential in understanding the behavior of AC circuits in various applications.
An inductor is a passive electrical component that stores energy in its magnetic field when current flows through it. It opposes any changes in the current passing through it. In a purely inductive circuit, the only component present is an inductor, and there are no resistors or capacitors in the circuit.
Key characteristics of a purely inductive circuit:
Phase Relationship: In a purely inductive circuit, the current lags the voltage by 90 degrees. This means that the current reaches its maximum value a quarter of a cycle (90 degrees) after the voltage reaches its maximum value. The voltage across the inductor leads the current by 90 degrees.
Voltage and Current Relationship: In a purely inductive circuit, the voltage across the inductor is directly proportional to the rate of change of current with respect to time. Mathematically, this can be expressed as: V = L di/dt, where V is the voltage across the inductor, L is the inductance of the coil, and di/dt is the rate of change of current.
Impedance: Impedance in an AC circuit is similar to resistance in a DC circuit. For a purely inductive circuit, the impedance (Z) is equal to the inductive reactance (XL), which is given by XL = 2πfL, where f is the frequency of the AC signal and L is the inductance of the coil.
Resonance: Purely inductive circuits are often encountered in the analysis of resonant circuits, particularly in series resonance. At resonance, the inductive reactance cancels out the capacitive reactance (if present) resulting in a higher current flow through the circuit.
Power Factor: In a purely inductive circuit, the power factor is lagging, and the apparent power (S) is equal to the reactive power (Q), with no real power (P) being consumed. This means that the energy oscillates between the source and the inductor without being dissipated as heat.
It's important to note that in real-world scenarios, purely inductive circuits are relatively rare because most circuits contain a combination of inductance, resistance, and capacitance. These components interact to create a variety of circuit behaviors, and their study is essential in understanding the behavior of AC circuits in various applications.