Calculate equivalent resistance for two to ten positive resistors in parallel, or estimate the nominal load of identical speakers wired all in series or all in parallel, in Ω, kΩ or MΩ.
Parallel Impedance Formula
The following reciprocal formula combines components in parallel. This calculator evaluates positive real resistances and nominal scalar speaker loads; general AC impedance requires complex-number calculations at the same frequency.
Zeq= 1 / [ (1/z1) + (1/z2) + (1/z3) + (1/z4) + (1/z5) ]
- Where Zeq is the equivalent parallel impedance (ohms)
- z1 through z5 are the five individual impedances in this example (ohms). The reciprocal sum extends to any number of parallel branches.
Parallel Impedance Definition
What is a parallel impedance? A parallel impedance is a measure of the equivalent impedance of a circuit whose components are assembled in parallel. In parallel circuits, the voltage is the same across every component.
Example Problem
How to calculate parallel impedance?
- First, determine the individual impedances.
For this example, we have impedances of 5 components which equal 10, 12, 20, 5, and 7 ohms, respectively.
- Next, use the formula to calculate the equivalent impedance.
Using the formula, we find the equivalent impedance to be: 1 / [ (1/10) + (1/12) + (1/20) + (1/5) + (1/7) ] = 1.736 ohms.
- Finally, use the equivalent impedance to solve your problem.
For these positive real-resistance inputs, you can use the result as the circuit’s equivalent resistance.
About Parallel Impedance
How to add parallel impedances? To combine parallel impedances, you must use the same formula that is displayed above, but instead of using the individual impedances, you would use the two or more calculated parallel impedances.
