Phys 4, Section
2
Feb 6, 2002
Power dissipation
Current flow through a resistor causes heating (called Joule heating
or resistive heating). This represents a loss of energy from the
system
Power is rate of doing work, so for electrical quantities,
dW = Vdq
P = dW/dt =Vdq/dt = VI = I^{2}R = V^{2}/R
Resistor Combinations
Parallel: 1/R_{eff} = 1/R_{1} + 1/R_{2}
+ ...
Series: R_{eff} = R_{1} + R_{2}
+ ...
Effective resistance of resistors in series is always more than the largest
resistor in the set, while the effective resistance of resistors in parallel is
always less than the smallest resistor in the set.
