Download Parallel Circuits

Parallel Circuits
Parallel Circuits
I
_
V
+
I1
I2
R
R
Parallel Circuit Rules
A parallel circuit has two or more paths
for current to flow through.
Voltage is the same across each
component of the parallel circuit.
VS = V1 = V2 = V3…
Parallel Circuit Rules
The sum of the currents through each
path is equal to the total current that
flows from the source.
IT = I1 + I2 + I3…
Let’s find the total Resistance
IT = I1 + I2 + I3…
Use V and R to find I:
VT V1 V2 V3
=
+
+
RT R1 R2 R3
VT V1 V2 V3
=
+
+
RT R1 R2 R3
Use: VS = V1 = V2 = V3
1
1
1
1
=
+
+
RT R1 R2 R3
Parallel Circuit Rules
The Total Resistance of a
Parallel Circuit is always less
than the smallest resistor.
Example
IT
_
I1
V
+
I2
R1
IT
I3
R2
R3
Given: V = 36V
R1 = 6 Ω
R2 = 9 Ω
R3 = 18 Ω
Find: RT = ?
I1 = ?
I2 = ?
I3 = ?
Example
Example
IT
_
I1
V
+
I2
R1
IT
I3
R2
R3
Given: V = 120V
R1 = 30k Ω
R2 = 30k Ω
R3 = 30k Ω
Find: RT = ?
I1 = ?
I2 = ?
I3 = ?
Example
RkΩ
1 30
2 30
3 30
Total
10
Comp
ImA VV PmW
4 120 480
4 120 480
4 120 480
12 120 1440
Example
IT
_
I1
V
+
I2
R1
IT
I3
R2
R3
Given: R1 = 6Ω
IT = 10mA
I2 = 3mA
I3 = 2mA
Find: RT = ?
VT = ?
II = ?
R2 = ? R3 = ?
Example
RkΩ
1 6
2 10
3 15
Total
3
Comp
ImA
5
3
2
10
VV
30
30
30
30
PmW
150
90
60
300