The Student Room Group

How does the variable resistor circuit provide a larger current?

Page 9 of file
Compare this arrangement for controling the current in the 8.0kOhm resistor witht he potential divider arrangement in Figure 2.
Everything in the mark scheme makes sense except from when it says the variable resistor can provide a larger current. If the potential divider circuit is in the configuration in which current is maximum, the pd across the 8.0kOhm resistor would be 9.0V (as pd across parallel branches is the same), which is the same as the variable resistor circuit. Therefore the maximum current of the variable resistor circuit would be the same as the potential divider circuit for the 8.0kOhm resistor. What's up?
Reply 1
I don't get it either - I'd say a valid comment about the potential divider is that the minimum current out of the battery is 9.0/4000 mA i.e. it's wasteful of the energy stored in the battery.

Quick Reply