Since there
is almost zero resistance in a ‘short’ circuit, it causes a problem of
excessive current in a series circuit which in turn, causes power dissipation
to increase many times and circuit components to burn out. The effect of short
circuit in a series circuit is shown with the illustration below.
is almost zero resistance in a ‘short’ circuit, it causes a problem of
excessive current in a series circuit which in turn, causes power dissipation
to increase many times and circuit components to burn out. The effect of short
circuit in a series circuit is shown with the illustration below.
Figure 1a
shows a normal series circuit where
Total
voltage (V) = 10V
voltage (V) = 10V
Total
resistance (R) = R1 + R2 + R3 = 9Ω
resistance (R) = R1 + R2 + R3 = 9Ω
Total
circuit current (I) = V/R = 10/9 =1.1A
circuit current (I) = V/R = 10/9 =1.1A
Power
dissipated in the circuit (P) = I2R = 1.12 X 9 = 10.89W.
dissipated in the circuit (P) = I2R = 1.12 X 9 = 10.89W.
In figure
1b, the 4Ω has been shorted out by a resistanceless copper wire so the RCD
= 0
1b, the 4Ω has been shorted out by a resistanceless copper wire so the RCD
= 0
Therefore
R = 2 + 3 +
0 = 5Ω
0 = 5Ω
I = 10/5 =
2A
2A
and P = 22
X 5 = 20W
X 5 = 20W
In figure
1c, both the 3Ω and 4Ω resistors has been shorted out of the circuit.
1c, both the 3Ω and 4Ω resistors has been shorted out of the circuit.
Therefore
R = 2 + 0 +
0 = 2Ω
0 = 2Ω
I = 10/2 = 5A
P = 52
X 2 = 50W
X 2 = 50W
Because of
the resulting excessive current due to the effect of the short (almost 5 times
the normal value), connecting wires and other circuit components can become hot
enough to ignite and burn out.
the resulting excessive current due to the effect of the short (almost 5 times
the normal value), connecting wires and other circuit components can become hot
enough to ignite and burn out.