Page 44 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

Fig 14

Appliction of ohms law in series circuit (Fig 15)

Applying ohms’ law to series circuit, the relation between various current could be stated as below
Ohm’s law state that I=V/R
In series circuit I=I =I =I R3
R1
R2
This could be stated as =V/R=V /R1+V /R2+V /R3
R2
R3
R1
Supply voltage V=V +V +V
R1 R2 R3
IR=R1I +R2I +R3I R3
R2
R1
Total resistance= R =R1+R2+R
Application of series circuit
• Cells in torch light
• Fuse in circuit

• Overload coil in motor starters
• Multiplier resistance of a voltmeter

Fig 15

Parallel combinatiom of resistance (Fig 16)
Parallel combination of circuit means two or more resistors its starting points are joined in a one point and other
ends of resistors are joined in another one point.
Parallel combination circuits are more used in house wiring installation
Voltages in parallel combination
Figure shows parallel circuit diagram. We can conclude that the voltage across the parallel circuit is the same as
the supply voltage
That is V=V1=V2=V3

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CITS : Power - Electrician & Wireman - Lesson 5 - 12