Mission EC7 Series Circuits Concepts
Hold down the T key for 3 seconds to activate the audio accessibility mode, at which point you can click the K key to pause and resume audio. Useful for the Check Your Understanding and See Answers.
Consider circuits X and Y below. Each circuit is powered by the same battery and contains identical resistors. Circuit X has one resistor and circuit Y has two resistors. The equivalent resistance of circuit X will be ____ that of circuit Y. The current in the battery in X will be ____ that in the battery in Y. Enter the two answers ... .
The equivalent resistance of a circuit is the amount of resistance which a single resistor would need in order to equal the overall effect of the collection of resistors which are present in the circuit.
The difference between circuit X and circuit Y is that circuit Y has more resistors than circuit X. The extra resistor in circuit Y is connected in series. The effect of the extra resistor on the overall or equivalent resistance of circuit Y is seen in the equation above in the Formula Frenzy section. Adding more resistors in series increases the overall resistance. The current in a circuit is directly related to the battery voltage (∆V) and inversely related to the equivalent resistance (Req). See the Know the Law section. Thus, an increase in the equivalent resistance would lead to a decrease in the current in the battery.
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
