7. ALTERNATING CURRENT
The chapter covers alternating current (ac) and its properties, particularly focusing on ac voltages and currents as they apply to resistors, inductors, and capacitors. Key topics include the phase relationships between voltage and current, the use of phasors for circuit analysis, resonant frequency in RLC circuits, and the function of transformers in altering voltage levels. The chapter concludes with various exercises and practical applications of these concepts.
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Sections
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What we have learnt
- Alternating currents exhibit sinusoidal voltage variations over time.
- The current through a resistor is in phase with the applied voltage, while it's not the case for inductors and capacitors.
- Resonance in RLC circuits occurs at a specific frequency where inductive and capacitive reactances cancel each other.
Key Concepts
- -- RMS voltage (V)
- The effective voltage value for alternating current, given by V = 0.707 * V_m, where V_m is the peak voltage.
- -- Inductive reactance (X_L)
- A measure of the opposition that an inductor offers to AC, defined as X_L = ωL.
- -- Capacitive reactance (X_C)
- The opposition that a capacitor offers to AC, defined as X_C = 1/ωC.
- -- Power factor
- The ratio of the real power flowing to the load to the apparent power in the circuit, defined as cos(φ), where φ is the phase difference between current and voltage.
- -- Transformer
- A device that changes the voltage level of alternating current through electromagnetic induction between coils.
Additional Learning Materials
Supplementary resources to enhance your learning experience.