Electric Circuits - Mission EC7 Detailed Help

Three identical light bulbs are connected to a battery as shown below. Which adjustments could be made to the circuit that would increase the current being measured at X? List all that apply ... .


 
Current in a Series Circuit:
The overall current in a series circuit is no different than the current in an individual resistor. That is, the current in the battery is the same as the current in resistor 1 or resistor 2 or resistor 3 or ... . Since there are no branching locations, current is never divided and is everywhere the same. The amount of current is related to the voltage (∆Vtot) impressed across the circuit by the battery and the overall equivalent resistance (Req). In equation form, these ideas can be written as
Ieq/ Rtot= ∆V3= I2= I1= Itot



 



 
For series circuits, the mathematical formula for computing the equivalent resistance (Req) from the resistance values of the individual resistors (R1, R2, R3, ...) is:
Req= R1+ R2+ R3+ ... 


 
The current measured at location X is the same as the current measured at any location on the electric circuit. For series circuits, current is everywhere the same. As mentioned in the Know the Law section, the amount of current at this location is directly related to the battery voltage and inversely related to the equivalent resistance. An increase in the battery voltage would cause the current at location X to increase. And a decrease in the equivalent resistance would cause the current at location X to increase. Decreasing the equivalent resistance can be done in a variety of ways. As shown in the Formula Frenzy section, the equivalent resistance is the sum of the individual resistance values. Any alteration made to the circuit which would reduce this sum results in an increase in current.