Chapter 3: Simple Resistive Circuits

Series-connected circuit elements

Elements that carry the same current

Combining Resistors in Series

if k resistors are connected in series, the equivalent single resistor has a resistance equal to the sum of the k resistances

black box

the term used to imply and opaque container (contents hidden from view)

Parallel-Connected Circuit Elements

elements that share the same voltage across them, allowing different currents to flow through each branch.

Combining Resistors in Parallel

the resistance of the equivalent resistor is always smaller than the resistance of the smallest resistor in the parallel connection.

Combining Two Resistors in Parallel

the equivalent resistance equals the product of the resistances divided by the sum of the resistances.

Voltage Divider

When voltage is divided between series-connected resistor

Current Divider

When current is divided between parallel-connected resistors,

Voltage Division

a circuit analysis tool used to find the voltage drop across a single resistance from a collection of series-connected resistances when the voltage drop across the collection is known

Current Division

a circuit analysis tool used to find the current through a single resistance from a collection of parallel-connected resistances when the current into the collection is known. where ij is the current through the resistance Rj and i is the current into the parallel-connected resistances whose equivalent resistance is R . eq

Voltmeter

measures voltage and must be placed in parallel with the voltage being measured.

Ammeter

measures current and must be placed in series with the current being measured

Digital meters and analog meters

have internal resistance, which influences the value of the circuit variable being measured and are based on the d ’ Arsonval meter movement deliberately include internal resistance as a way to limit the current in the movement’s coil.

Wheatstone Bridge

used to precisely measure medium value resistances of an unknown resistor, Rx with 3 resistors, a de voltage source (i.e. battery), and a galvanometer (detector)

Y/T to Delta/pi

equations used to transform a Y/T circuit to a Delta/pi circuit

Delta/pi to Y/T

equations used to transform a Delta/pi circuit to a Y/T Circuit