Electronics Handbook/Circuits/Current Divider

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.

 

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