Parallel Resistance Calculator
Quickly and professionally calculate the equivalent resistance of parallel resistors. If you enter the source voltage, you can also see the total current, total power, and the current passing through each resistor branch. Send the result to ONX Control engineers to request support for your application.
Circuit Configuration
Dynamic InputBase Equation
Parallel CircuitIn parallel connected resistors, the source voltage is the same across all branches. As the resistance decreases, the current passing through that branch increases, and the total equivalent resistance decreases.
Resistor Branches
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Live AnalysisBranch Currents
If Voltage EnteredIf the source voltage is entered, the current passing through each resistor branch is shown separately. In a parallel circuit, the voltage across each branch is identical.
Engineering Expert Window
Current divides in a parallel circuit: The source voltage is the same in all branches. More current flows through the branch with lower resistance value. Therefore, the power dissipation may be different in each resistor.
Equivalent resistance decreases: Every time a new resistor is added to the parallel branch, total conductance increases, hence the equivalent resistance decreases. The result is always smaller than the smallest resistor in the circuit.
How to Calculate Equivalent Resistance in a Parallel Resistor Circuit?
In parallel-connected resistors, the equivalent resistance is not found by directly adding the resistors. Instead, the sum of the reciprocals of each resistance is taken, and the reciprocal of the result is found. Therefore, the total resistance in a parallel circuit is always lower than the smallest resistor in the circuit.
If the source voltage is known, the total current can be calculated from the equivalent resistance. Also, since the voltage across each parallel branch is the same, the current of each branch can be determined separately. This approach is highly beneficial in shared load, current sharing, and power distribution analyses.
This tool prepared by ONX Control takes basic parallel resistance calculation further, showing branch currents and total power values along with the equivalent resistance. It is particularly suitable for quick preliminary checks in braking resistor combinations, heater banks, measuring circuits, and load sharing analyses.
Frequently Asked Questions
Why does equivalent resistance decrease in a parallel circuit?
Because each new parallel branch creates an additional path for the current. Total conductance increases, and as a result, equivalent resistance decreases.
Is the voltage the same across all resistors in a parallel circuit?
Yes. Since all parallel connected branches are between the same two nodes, the voltage across each branch is identical.
Which current does the smallest resistor carry?
When the source voltage is constant, the branch with the smallest resistance value carries the highest current.
Can this tool be used for braking resistors or parallel load banks?
Yes, for preliminary analysis. However, in actual applications, thermal power, continuous/peak load regime, and component tolerances must be additionally evaluated.
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