الفيزياء العامة الجزء الثاني#موقع الفيزياء.كوم

7.7.2 Resistors in Parallel:
Lectures in General Physics
The figure 7.5 shows three resistor in parallel, between the points A and B,
A current I enter from point A and leave from point B, setting up a potential
difference V AB .
R 1
I 1
I 2
A
R 2
B
I 3
R 3
V AB
Figure 7.5
For a parallel connection of resistors, the potential difference is equal
across each resistor.
The current branches into I 1 , I 2 , I 3 , through the three resistors and,
I=I 1 +I 2 +I 3 (7.22)
The current in each branch is given by
I
1
VAB
= ,
R
1
I
2
VAB
= ,
R
2
I
3
V
=
R
⎛ 1 1 1 ⎞
∴ I = V
⎜ + +
⎟
AB
(7.23)
⎝ R1
R2
R3
⎠
The equivalent resistance is
AB
3
1 1 1 1
∴ = + +
(7.24)
R R R R
1
2
3
Dr. Hazem Falah Sakeek