Once the equivalent resistance is known, a new circuit is drawn consisting

of a single resistor (to represent the equivalent resistance) and the

voltage source, as shown in view B.

b. *Rules for Parallel Circuits.*

Rule 1: The same voltage exists across each branch of a parallel circuit and

is equal to the source voltage.

Rule 2: The current through a branch of a parallel network is inversely

proportional to the amount of resistance of the branch.

Rule 3: The total current of a parallel circuit is equal to the sum of the

individual branch currents of the circuit.

Rule 4: The total resistance of a parallel circuit is found by the general

formula:

or one of the formulas derived from this general formula.

c. *Solving Parallel Circuit Problems.*

Problems involving the

determination of resistance, voltage, current, and power in a parallel

circuit are solved as simply as in a series circuit. The procedure is the

same: (1) draw the circuit diagram, (2) state the values given and the

values to be found, (3) select the equations to be used in solving for the

unknown quantities, based upon the known quantities, and (4) substitute the

known values in the equation you have selected and solve for the unknown

value.