8th grade ch. 2 sec. 4 electrical circuits

Ch. 2Sec. 4

Electrical Circuits

Ohm’s Law

• Resistance= Voltage (volts)

(ohms) Current (amps)

R=V V=C X R

C

Ohm’s Law• Resistance= Voltage (volts)

(ohms) Current (amps)

Resistance= 10 ohms

Voltage= 20 volts

Current= ?

10= 20

C

Current = 2 amps

Ohm’s Law• Resistance= Voltage (volts)

(ohms) Current (amps)

Resistance= ?

Voltage= 60 volts

Current= 2 amps

Find the missing variable.

Resistance Voltage Current

75 volts 25 amps

100 volts 2 amps

2 ohms 80 volts

4 ohms 120 volts

• Resistance= Voltage (volts)

(ohms) Current (amps)

measured with unit

voltage voltmeter Volt

current ammeter amp

resistance multimeter Ohm

basic features of a circuit:

1. source of electrical energyeg. battery

2. have device run by electrical energyeg. light bulb

3. connected by conducting wires & switch= used to open & close circuit

closed- circuit complete open- circuit broken

Electrical Flow [02:04]

resistor• uses electrical energy as it interferes w/ flow of charge

Series and Parallel Circuits [00:36] .

2 types of circuits: series & parallel

seriescircuit

only 1 path

for current to take

advantage disadvantages

simple to build

if 1 light goes out-

all go out

more bulbs added-

greater resistance

series series circuitcircuit

Christmas tree lights

series series circuitcircuit

several pathsfor current

to takeadvantage

more branches added-

decreased resistance

if 1 light goes out-

other stay lit

household household circuits-circuits-parallel parallel circuitscircuits

series circuits vs. parallel circuits

comparing circuits slideshow

Series and Parallel Circuits [02:02]