Download Introduction to DC Parallel Circuits

Introduction to DC Parallel
Circuits
Online Resource for ETCH 213
Faculty: B. Allen
Parallel circuit
( Also called shunt ): a circuit having two or
more paths for current flow.
Online Resource for ETCH 213
Faculty: B. Allen
Voltage in a parallel circuit
VS=VR1=VR2=VR3=……
Online Resource for ETCH 213
Faculty: B. Allen
Current in a parallel circuit
Branch Current – A portion of the total
current that is present in one path of a
parallel circuit.
Kirchhoff’s Current Law – The sum of the
currents flowing into a point in a circuit is
equal to the sum of the currents flowing out
of that same point.
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Faculty: B. Allen
Kirchhoff’s Current Law
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Current in a parallel circuit
IT = I1+I2+I3+…….
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IT = (VS/RT)
In a parallel circuit, the total current equals
the source voltage divided by the total
resistance.
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Faculty: B. Allen
Series circuit and parallel circuit
current comparison
Online Resource for ETCH 213
Faculty: B. Allen
Branch current
IX = (RT/RX)IT
IX = Branch current
RT = Total resistance
RX = Branch resistance
IT = Total current
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Faculty: B. Allen
Conductance in a parallel circuit
Conductance (G) = 1/Resistance = 1/R
In a parallel circuit:
Total conductance GT =
GR1 + GR2 + GR3 + …
Online Resource for ETCH 213
Faculty: B. Allen
Resistance in a parallel circuit
1
Total Re sis tan ce =
1
1
+
+ ...
R1 R2
OR
1
1
1
1
= +
+
+ ...
RT R1 R2 R3
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Faculty: B. Allen
For two resistors in parallel
R1 × R2
RT =
R1 + R2
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For equal-value resistors in
parallel
RT =
Value of one resistor / Number of resistors
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Power in a parallel circuit
PT = P1 + P2 + P3 + …
Formulas for calculating power
P=I×V
P = V2/R
P = I2×R
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Faculty: B. Allen
Parallel circuit example
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Troubleshooting a parallel
circuit
An open component causes IT
A shorted component causes IT
.
.
and the fuse to blow, causing the circuit to
open.
Variations of a component value may cause
IT or IT .
Online Resource for ETCH 213
Faculty: B. Allen
This ends
Introduction to DC Parallel
Circuits
Online Resource for ETCH 213
Faculty: B. Allen