Page 205 - WCS - Electrical

Example
Two resistors of 2 and 4 ohms are switched in parallel
to a 6V battery
WORKSHOP CALCULATION & SCIENCE - CITS
– Calculate the total resistance
– Find the total current and partial current.

Solution
Solution
Total resistance
• The total resistance of a parallel connection is always Total resistance
smaller than the smallest resistance in the circuit.
1 1 1
• In parallel connection the reciprocal of the total R = R + R
resistance is equal to the sum of the reciprocals of all tot 1 1 2 + 1 2
1
resistances in the circuit. = + =
2 4 4
l = l + l + ...
1 2 = 3 Ω
V = V = V ... 4
2
1
R = 4 = 1 1 Ω
1  1  tot 3 3
1
..........


R R R
1 2 I Total = I + I current
1
2
Example U 6V
But I 1 = = = 3A
Two resistances of 4 ohms and 6 ohms are connected in R 1 2Ω
parallel. Determine the total resistance. U 6V
I 2 = = = 1.5A
R 2 4Ω
1 1 1

1.5A

  I total 3A = +
R R R (since parallel connection)
1 2 4.5= Amp
Assume the given resistors in the assignment as bulb with filaments and other current consuming
1 1 1 10 Assume the given resistors in the assignment



Therefore  devices like Horn, Wiper etc of the vehicle.
as bulb with filaments and other current con-
R 4 6 24
suming devices like Horn, Wiper etc of the
Assignment
24 vehicle.

Therefore R  ohms = 2.4 ohms
10
1 R = 40 Ohms
I = 6.5 Amps
Assignment V = ______ Volts
1 R = 40 Ohms 2 V = 6 Volts
I = 6.5 Amps I = 0.5 Amps 2 V = 6 Volts
V = ______ Volts R = ______ Ohms
I = 0.5 Amps
R = ______ Ohms

Workshop Calculation & Science : (NSQF) Exercise 1.7.35 109

192

CITS : WCS - Electrical - Exercise 18