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Rotating Generators and Faraday’s Law. 0. For N loops of wire. Alternating Current. AC Generator and a Resistor. AC Power. ?. Root Mean Square (rms) . Inductive Circuits. Inductive Reactance. Capacitive Circuits. Capacitive Reactance. Voltage transformers. Current in transformers.
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Rotating Generators and Faraday’s Law 0 For N loops of wire
AC Power ?
Inductive Circuits Inductive Reactance
Capacitive Circuits Capacitive Reactance
Current in transformers Actually currents are 180 degrees out of phase
Example: transformers What is Vs ?
LC Circuits Solution: Kirchhoff Loop Equation:
Active Figure 32.17 (SLIDESHOW MODE ONLY)
LRC Circuits Kirchhoff Loop Equation: Solution:
Damped RLC Circuit • The maximum value of Q decreases after each oscillation • R < RC • This is analogous to the amplitude of a damped spring-mass system
Active Figure 32.21 (SLIDESHOW MODE ONLY)
LRC Circuits • Underdamped • Critically Damped • Overdamped
Resonance Power: Power Factor What is Power factor at Resonance?
41. An emf of 96.0 mV is induced in the windings of a coil when the current in a nearby coil is increasing at the rate of 1.20 A/s. What is the mutual inductance of the two coils? 49. A fixed inductance L = 1.05 μH is used in series with a variable capacitor in the tuning section of a radiotelephone on a ship. What capacitance tunes the circuit to the signal from a transmitter broadcasting at 6.30 MHz? 55. Consider an LC circuit in which L = 500 mH and C = 0.100 μF. (a) What is the resonance frequency ω0? (b) If a resistance of 1.00 kΩ is introduced into this circuit, what is the frequency of the (damped) oscillations? (c) What is the percent difference between the two frequencies?
LC Demo R = 10 W C = 2.5 mF L = 850 mH • Calculate period • What if we change • C = 10 mF • Underdamped? • How can we change damping?