DC Fundamentals Unit 8 – Parallel Resistive Circuits
When S1 is closed, a second 1 kΩ resistor, R2, is connected in parallel with R1 to provide an
additional path (IR2) for current. Because R2 is connected across the voltage source in the same
way as R1, the voltage source causes current to flow through R2.
In a parallel circuit, total current (IT) equals the sum of the branch currents.
With two current paths, the total current (IT) supplied by the source is the sum of the two branch
currents (IT = IR1 + IR2).
Total circuit resistance equals the voltage source divided by total circuit current. To calculate
total resistance, apply the product-over-sum formula.