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.