Electronics Handbook/Circuits/Current Divider

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Current Divider[edit]

If two elements are in parallel, the voltage across them must be the same, but the current divides according to the resistances. A simple circuit with two (or more) resistors in parallel with a source is called a current divider.

Resistorsparallel.png

Figure B: Parallel Resistors.

Mathmatic Formula[edit]

If a voltage V appears across the resistors in Figure B with only and for the moment then the current flowing in the circuit, before the division, i is according to Ohms Law.

Using the equivalent resistance for a parallel combination of resistors is

(1)

The current through according to Ohms Law is

(2)

Dividing equation (2) by (1)

Similarly

In general with n Resistors the current is

Or possibly more simply

Where