An electric circuit is simply a closed loop through which charges can continuously move. An electric circuit basically contains a source of electricity, a load resistance, a switch or a key for turning the circuit on or off at one’s convenience. If the starting ends of two resistors are joined to a point, and the terminal ends of the two are combined and given connection to a source of electricity, those circuits are called Parallel Circuit. Unlike in the series circuit, the current in each branch of a parallel circuit will be different. If one branch is broken, current will continue flowing to the other branches. At our homes all the electronic appliances are connected in parallel with each other. This means they all get the full mains voltage, so that we can turn on the TV without having to turn on the microwave as well. Given two resistors, R1 and R2, in parallel, the equivalent resistance, Rt, is: 1/Rt = 1/R1 + 1/R2. That is, for a set of parallel resistors, the reciprocal of their equivalent resistance equals the sum of the reciprocals of their individual resistances.
This video explains how to determine the equivalent resistance of two resistors when connected in parallel.