Example 3:
Find the voltage when the current is 4 amperes and the resistance is 3
ohms.
E = I x R = 4 x 3 = 12 volts
4.
SERIES CIRCUITS
a. Resistance.
A series circuit is one in which the resistances or other
electrical devices are connected end to end so that the same current flows in each
part of the circuit. Each part of the circuit adds its opposition to the flow of
current to the opposition offered by every other part.
An example of a series
circuit is shown in figure 4. Each resistor opposes the flow of current from the
power source. The total opposition is therefore the sum of the resistances of all
five resistors. The resistor having the highest resistance value will develop the
largest value of voltage across it.
Figure 4.
Series-resistive circuit.
b. Current.
Since all components of the circuit under discussion are in
series, it is evident that the same current that flows through any one component
flows through all components included within the circuit.
The total value of
current is therefore proportional to the total opposition to the flow of current
and to the applied voltage.
It is also evident that the current leaving the
circuit must be of the same value as that entering the circuit.
308
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