RESISTORS AND ELECTRIC POWER
Resistors are passive components
that can only absorb energy.
Combining Ohm’s law and the
expressions for power we can derive
several useful expressions
Problem solving tip
: There are four
variables (P,v,i,R) and two equations.
Given any two variables one can find
the other two.
If not given, the reference
direction for voltage or current
can be chosen and the other is
given by the passive sign convention
A MATTER OF UNITS
Working with SI units Volt, Ampere
Watt, Ohm, there is never a problem.
One must be careful when using
multiples or sub multiples.
The basic strategy is to express
all given variables in SI units
