Current Divider Rule: All Important Things you need to Know about CDR

In series circuits electric current always remains the same. However in parallel circuits, the current is not the same, instead, it is different based on the resistance of components. The Current Divider rule is used to determine how current splits at the node and how does it divide among parallel components. In this post, you’ll learn all about current divider.

The formula

In figure above, two resistors Rx and R1 are connected in parallel.

The equation Ix is the CDR formula.

Mathematically: Current divider rule formula Ix = (Rt/Rx) * It

where Rt is the parallel equivalent resistance of Rx and R1.

An Example

Consider a circuit having 10 Amps current source and two resistors R1 and R2. Using CDR formula we can find the current flowing through both resistors:

Some Quick Points to remember

  • Two equal resistors in parallel will have equal current flowing across them
  • The higher the amount of resistance is, the lower will be the current (This is in accordance with Ohm’s law)
  • A very small resistance in parallel with a large resistance will have almost all the current dissipated across it
  • For any number of equal resistances, the overall current will be equally dissipated among the individual resistors

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