Ch 07 - Alternating Current12th Physics
Alternating Current (AC)
What fundamental characteristic distinguishes Alternating Current (AC) from Direct Current (DC) over time?
What fundamental characteristic distinguishes Alternating Current (AC) from Direct Current (DC) over time?
Explanation:
- Alternating Current (AC) is an electric current whose magnitude changes continuously with time and its direction reverses periodically.
- In contrast, Direct Current (DC) flows in a single, constant direction without reversing.
- AC is widely used because it can be easily and efficiently converted between voltages using transformers.
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AC Alternates, DC is Direct
General Equation of Alternating Current
General Equation of Alternating Current
State the formula that mathematically represents an alternating current oscillating sinusoidally over time.
Variables & Units:
- I = Instantaneous current (A)
- I_0 = Peak current or amplitude (A)
- \omega = Angular frequency (rad/s)
- t = Time (s)
Conditions/Notes:
- The angular frequency is related to the time period by and linear frequency by .
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Mean Value of AC (Full Cycle)
Why is the average value of an alternating current over one complete cycle exactly zero?
Why is the average value of an alternating current over one complete cycle exactly zero?
Explanation:
- An AC wave oscillates symmetrically, meaning it has corresponding positive and negative values of equal magnitude during each complete cycle.
- The sum of the instantaneous current values over the positive half-cycle exactly cancels out the negative half-cycle.
- Therefore, the net charge transferred in either direction over a full cycle is mathematically zero.
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Also in this chapter
38 more cards to study in Prism
- 4Mean Value of AC (Half Cycle)
- 5Root Mean Square (RMS) Current
- 6RMS Current & Voltage
- 7Measurement of AC Current
- 8AC in Electrolysis and Battery Charging
- 9Phasors and Phasor Diagrams
- 10Inductive Reactance Formula
- 11AC Circuit with Pure Resistance
- 12AC Circuit with Pure Inductance
- 13Capacitive Reactance Formula
- 14AC Circuit with Pure Capacitance
- 15Impedance of Series LCR Circuit
- 16Extreme Frequency Behavior of L and C
- 17Phase Angle in Series LCR Circuit
- 18Power Dissipation in Pure L and C
- 19Phasor Analysis of Series LCR Circuit
- 20Resonant Frequency Formula
- 21Algebraic vs. Vector Addition of AC Voltages
- 22Quality Factor Formula
- 23Average Power & Power Factor
- 24Series Electrical Resonance
- 25Quality Factor (Q-Factor)
- 26Energy Stored in an Inductor
- 27Real Power vs. Apparent Power
- 28Transformer Voltage and Turns Ratio
- 29Wattless Current
- 30Choke Coil Application
- 31Transformer Current Ratio (Ideal)
- 32LC Oscillations
- 33LC Circuit vs. Spring-Mass Analogy
- 34Transformer Working Principle
- 35Transformer Core Lamination
- 36Step-Up vs. Step-Down Transformers
- 37Transformer Copper & Iron Losses
- 38Differential Equation of Series LCR Circuit
- 39Transformer Flux Leakage & Hysteresis
- 40Transformer Efficiency Formula
- 41Long-Distance AC Power Transmission
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