Power
Dissipated in a Circuit
Figure
1
Find the power
dissipated in the 10 ohm resistor for the circuit (Figure 1).
Solution:
First, we find the resistance
of the parallel section:
Thus, the equivalent resistance
of the circuit is 4.55 ohms.
The total current is 12 V/4.55
ohms = 2.64 A
The voltage drop across the
3 ohm resistor is
(2.64 A)(3 ohms) = 7.91 V
The 10 ohm and the 6 ohm resistors
are in series, so these two equal 16 ohms:
V16 = Vpara
= 12 - 7.91 = 4.09 V
I6 = I10
= I16 = 4.09 V/16 ohms = 0.255 A
The power dissipated in the
10 ohm resistor is
