Voltage Across Parallel Resistances:

Suppose now a set of ornamental light bulbs are connected in parallel. This is the technique used for outside holiday lighting or for bright indoor lighting. You know that it is much simpler to fix a parallel-wired string of holiday lights when one bulb must burn out than it is to fix a series-wired string. The malfunction of one bulb does not cause catastrophic system crash. However, it may be awhile before you observe that the bulb is dark since all the other ones will remain lit, and their brightness will not change.

In a parallel circuit, the voltage across each component is always same and is always equivalent to the battery voltage or supply. The current drawn by each component depends only on the resistance of that specific device. In this logic, the components in a parallel-wired circuit work separately, as reversed to the series-wired circuit, in which they all act together.

When any branch of a parallel circuit is taken away, the circumstances in the other branches stay the same. When new branches are added, supposing that the power supply can handle the load, situations in formerly existing branches are not affected.