Current Divider Formula

Go to current divider calculator.

Current divider is actually two resistors connected in parallel.

current-divider-circuit

Now, if we know input current and R1 and R2 resistor value, we can calculate how input current will split up, i.e. how much are I1 and I2. By intuition, if R1=R2 then input current is split into two equal halves. But how to obtain exact current divider formula? First step is to find voltage drop across the resistors by using Ohm’s law.

current-divider-eq1

Knowing voltage, we can find current through each resistor, again by using Ohm’s law. So current divider formula for currents I1 and I2 are respectively

current-divider-formula-I1

and

current-divider-formula-I2

What is interesting is that current through resistor R1 is directly proportional to resistor R2 value, while current through resistor R2 is directly proportional to resistor R1 value. It might be confusing at the first glance, but it is quite logical. If neighboring resistor is large, more current will flow through out given resistor and vice versa.

Go to current divider calculator.

External links:

Current Divider on Wikipedia
Current Divider on Allaboutcircuits
Current Divider on Learningaboutelectronics

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