A parallel circuit can be identified by the presence of a consistent potential difference (voltage) across the ends of all of the resistors.
When resistors are connected in parallel, the equivalent resistor has a value that is lower than the resistor that has the lowest value among the resistors that are connected in parallel. Because adding a new resistor in parallel creates a new path for current to follow, the total current after adding the new resistor is higher than the value it was before adding the new resistor; consequently, the total resistance is always lower than the resistance it had been before adding the new resistor.
RT = equivalent parallel resistance
R1, R2 = resistances of individual resistors
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