3 rlc circuits
DESCRIPTION
RLC CircuitsTRANSCRIPT
RLC Circuit
AP Physics C Mrs. Coyle
RLC circuit
• In real circuits, there is some resistance, and some energy is lost to internal energy for the resistor (heat).
• (Some energy is also lost to radiation but this is ignored).
• Therefore the total energy of the circuit decreases over time similar to damping in a mass-spring system.
Remember:LC Circuits• Assume the capacitor is initially charged and then the switch is closed
• Assume no resistance (no internal energy loss) and no energy losses to radiation
• The total energy of this system is constant
221
2 2IC L
QU U U L
C
Simulation
http://phet.colorado.edu/en/simulation/circuit-construction-kit-ac
RLC Circuit The capacitor is charged with the
switch at position a. At time t = 0, the switch is moved
to position b to form the RLC circuit.
Kirchhoff’s loop rule:
0 and q dI dq
L IR , IC dt dt
22 2
2
10 and
d q R dqq ,
dt L dt LC
RLC Circuit
221
with 2
RtL
max d d
Rq Q e cos t ,
LC L
2
2
RtL
max d d d
RI Q e sin t cos t
L