To calculate equivalent resistance in a parallel circuit, which equation is applied?

In a parallel circuit, the equivalent resistance is calculated using the reciprocal equation. This equation emphasizes that the total resistance decreases when more resistors are added in parallel, as each additional path offers an alternate route for current flow. The formula for calculating the equivalent resistance (R_eq) in a parallel circuit is given by the reciprocal of the sum of the reciprocals of each individual resistance (R_1, R_2, R_3, etc.):

1/R_eq = 1/R_1 + 1/R_2 + 1/R_3 + ...

By taking the reciprocal of this summed value, you determine the overall resistance of the circuit. This characteristic of parallel circuits contrasts with series circuits, where resistances are additive. Thus, applying the reciprocal method accurately reflects how current divides among the branches and leads to the correct calculation of equivalent resistance.