Lesson 5 – Introduction to Circuits - Stambytes

amountdollΗλεκτρονική - Συσκευές

2 Νοε 2013 (πριν από 3 χρόνια και 5 μήνες)

66 εμφανίσεις

INTRODUCTION TO
CIRCUITS

Text 11.2: Page 448
-
453

Agenda

1.
What are Circuits?

2.
Drawing Circuits

3.
Types of Circuits


Series


Parallel

4.
Transistors

5.
Activity!


Learning Goals


By the end of this
class we should be
able to:


Draw and construct circuit diagrams based on given
diagrams or circuits


Compare and contrast
current and
resistance in series
and parallel circuits

What is a Circuit?


Circuit Diagrams


Standardized symbols, like a language, used to
communicate the parts of a circuit


Circuit Diagrams


It is very important these
diagrams are always
very neat and tidy!


Always use straight lines
drawn with a ruler


Always use right angles
when connecting corners

Series Circuits


Is a circuit in which the
components are arranged
one after another in a series


There is only one path through
which the electrons can flow


If any one part of the series is
damaged or
interrupted the
whole circuit cannot function


Resistance


The amount of current is
the same in all parts of
the
series


BUT if
you
add
resistors
you increase the resistance
of the whole circuit which
decreases the current


i.e. if you add a second
bulb both bulbs become
dimmer


Parallel Circuits


An electric circuit in which the
parts are arranged in which
the electrons can move along
more than one path


Points where the circuit
divides
and combine
are called
junctions


An interruption or break in one
part of one pathway does not
affect the other pathways in the
circuit


Parallel Circuits


A
dding
more resistors or
new
pathways
does not
affect the resistance in
any other pathway


In
contrast,
adding extra
resistors in a parallel circuit
decreases the total
resistance of the circuit


Water Analogy


Think of the Water Analogy


The more
straws sucking
water the less resistance of
water (Parallel Circuits)


Most electrons will follow the
path with the smallest
resistance values


Therefore more current in paths
with lowest resistance


Summary Table


Hmmm….


Combinations


Series and parallel
can be combined


This is used when
designing circuits in
your home


i.e. won’t put a light
bulb and your fridge
in a series circuit
because if it burns out
fridge will go off


Transistors


Used to control voltage or currents


i.e
. to make
voltage/current larger
or smaller on either side of the
transistor


A tiny device that acts as a switch
or
amplifier to make
current or
voltage
greater


EX:
in microphones electric signals
are amplified to make
sound louder
by the circuit


T
ransistors


Transistors are also
known as
solid state
components


Made of solid materials
with no moving parts


Usually made of 3 layers
of specially treated layers
silicon


Your Turn to Try!