ITP 150 Unit 5

When resistors of equal value are connected in series, they will develop voltage drops of_____ value.

equal

In a circuit, resistors of equal value are connected in series. One of the resistors malfunctions and shorts the circuit. The voltage drops across the remaining resistors will:

increase

Two 25 ohm resistors connected in series will require_________ voltage source to produce a 6 volt voltage drop across one 25 ohm resistor.

12V

How much voltage will be found across a blown fuse?

whatever the source voltage is

How much is the voltage drop across a shorted resistor?

it is equal to zero

What is the total resistance of a twelve-ohm and an eight-ohm resistor connected in parallel?

4.8 ohms

Applications of series circuits

batteries, string lights, thermostats, electric water heater

voltage drops in a series circuit

voltage divided at every load

total voltage applied =

sum of all the voltage drops

resistance total in a series circuit

sum of all the resistor values

currents, formula in a series circuit

the same everywhere (total V = I x total R)

power in a series circuit

sum of power dissipated by each resistance or total P = total E x I

open circuit

switch is open, fuse/resistor burned out

short circuit

 resistor is burned but metal wire is still touching (connected/jumper wire)

open circuit in a series circuit (I, V, R)

no current, voltage is the total source voltage applied, infinite resistor

short circuit in a series circuit (R, I, V)

0 resistance, increased total current, voltage drop 0

applications of parallel circuit

everything in a house, appliances in the house, automobile lighting circuit, power strip

series circuit is a ____ divider

voltage

parallel circuit is a ____ divider

current

parallel circuit: electron flow

electrons are divided into multiple paths (path with less resistance takes more)

total current in a parallel circuit

add all of the individual currents

parallel circuit: main line current

current entering/exiting voltage source (the same)

parallel circuit: branch current

individual current

resistance total (more than two) in a parallel circuit

(1/R1 + 1/R2 +…_) ^-1

resistance total (only 2) in a parallel circuit

R1xR2/R1+R2

voltage in a parallel circuit

constant

total resistance is more or less than the value of any of the resistors in the branches of a parallel circuit

less

current drop across ressitors in a parallel circuit

use ohm’s law with individual resistors to find individual currents

power dissipation in a parallel circuit

power = voltage x current, not split evenly across all resistors

open resistor in a parallel circuit (R, I)

infinite R, no current

short resistor in a parallel circuit (R, I, where does current go)

zero R, increase total I, current goes to the shorted branch due to no resistance

another way to calculate total resistance in a parallel circuit

total resistance = value of one resistor / number of resistors

troubleshooting a parallel circuit measure:

current

troubleshooting a series circuit measure:

voltage