Download Circuits

Circuits
Chapter 2
2.1 Charge Needs a Path
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Charge will not flow through a material
unless it forms a closed path or loop
Circuit – a closed path though which
continuous charge can flow
Parts of the Circuit
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Voltage Source:
Provides electric potential
 Ex: Batteries, Powerplant
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Parts of the Circuit
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Conductor
Completes the path from the power
source to the electrical device and back
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EX: Copper Wire
Parts of the Circuit
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Switch – Allows the opening and closing
of a circuit
When open- No current flows
EX: Light Switch
Parts of the Circuit
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Electrical Device – Changes electrical
energy into another form of energy like
heat, light, or to do work
Resistors – Slow down the flow of
electricity Ex: Lightbulb
Open Circuit
Closed Circuit
Drawing a Circuit
Path of Least Resistance
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The path does not always have to be a
wire, it can be anything that conducts
Its easier to flow through you than the
device you are plugging in
Short Circuits
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An unintended path connecting one part
of the circuit with another.
Causes overheating and may cause a fire
=
DO NOT TOUCH
Grounding

Some plugs have a 3rd prong, which will
channel excess electricity during a
short to the ground.
Safety Devices

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Overloading the circuit – too many
things plugged in, or a short occurs
Fuses: Open a circuit when too much
power is drawn by melting a metal rod.
Safety Devices

Older Houses use fuses
Safety Devices

Newer Houses = Circuit Breaker
Ground Fault Circuit
Interrupter (GFCI)

Used in areas around water
2.2 Useful Circuits

Current is used because it is
Easy to store
 Easy to distribute
 Easy to turn on and off

Types of Circuits
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A light switch that turns on more than
one light can either have a series or
parallel circuit
Series Circuit

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Current follows a single path
All parts are part of the same circuit
Disadvantages
All elements must be in working order
 If one bulb burns out, the
rest go out
EX: Christmas Lights

Series Circuit
Parallel Circuit

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Current flows in more than one path
Voltage is the same throughout the
circuit
If one bulb burns out, the rest will still
burn
All wall sockets and switches are
Parallel
Parallel Circuits
Batteries in a Series

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Positive to negative of another battery
Voltages add together
Batteries in Parrallel

Will not add voltage, but lasts longer
2.3 Coded Information

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Code – a system of symbols used to send
a message
Words are a code that send a message
with symbols (Letters)
Electronic Devices use electric current
to send information in code
Binary Code

English Language = 26 letters


Unlimited number of messages
Binary Code = 2 choices
Like Playing 20 questions (yes/no)
 Current On/Current Off
 Messages are sent in electric pulses
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Digital Information

Binary Code uses 2 numbers (0,1)
0 = closed circuit
 1 = open circuit
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Each 0 or 1 is known as a bit
Group of 8 is known as a byte
Gigabyte = 1 billion bytes
Uses
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Computers, MP3 Players, DVD’s
Why
Digital info can be copied many times
without loss of quality
 Digital info can be worked with on
computers

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Ex: A digital photograph can be
modified on a computer
Analog

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Analog – information that is
represented in a continuous but varying
form
Examples:
Sound recorded on a cassette tape
 VHS
 Records

Analog to Digital

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1) Sound is picked up in analog
2) A computer amplifies the sound and
measures the sound waves
3) The sound waves are converted into
digits (0,1) and imprinted on a CD
4) CD Player turns digital back to analog
Integrated Circuits
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A small circuit with switches that turn
on and off sending binary code to a
device
Over a million switches can be in one IC
Integrated Circuit
Computers

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Hardware – Hard parts
Software – Programs to run the
hardware
Memory
RAM – Short Term Memory
 ROM – Long Term Memory
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Computer Use

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1) Input – Information is put into the
computer
2) Storage – stored on a hard drive
using (1,0)
Processing – Info turned back into
(text, photographs, sounds etc.)
Output - Printing
Internet

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Originally –
computers were
originally hooked up
on college campuses
Acted like a series
circuit – one
computer goes out
they all go out!!!

ENIAC - 1946
Internet Today
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Host computers (Servers) have files
that you can access
WWW = World Wide Web