# Current does not always choose the path of least resistance...?

1. Sep 29, 2015

### fog37

Hello Forum,

Electric current usually goes down the path of least resistance if it can. However, there are situations in which it prefers to go through a path of more resistance if the path of least resistance has no potential difference across.
Are my statements correct?

For example, see the circuit below where the current does not pass through the red segment of the circuit because it has no potential a difference across and could be removed without affecting the circuit:

thanks!

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2. Sep 29, 2015

### Jeff Rosenbury

Yes, your statement is correct. Current does not always follow the path of least resistance. Your example is a little misguided though.

Current travels in loops. so the entire loop resistance needs to be considered.

But suppose we have a 100Ω resistor in parallel with a 99Ω resistor. Some current will flow in each rather than all of it flowing in the path of least resistance, the 99Ω resistor.
(More will flow in the 99Ω than the 100Ω though.)

Also there are capacitance, inductance, and occasionally relativistic effects that affect the current flow.

3. Sep 29, 2015

### epenguin

It goes through all paths. Some goes through the bird perching on the high voltage electric supply cables. But it goes in the 'laziest' way possible, it goes in such a way that it heats (aka dissipates energy) the least possible, given the constraints. So it mostly goes through the cable not the bird. There was a thread about it by a guy who discovered this (not the first unfortunately) here.