2. Circuit Defined
A circuit is a path for
electrons to flow
through. The path is
from a power source’s
negative terminal,
through the various
components and on to
the positive terminal
Types
Series
Parallel
2
4. Components - Load
LIGHT BULB
lights up when
electricity pass through
4
5. Circuit - Complete
Source of electrical energy
Appliances
Complete circuit
-
+
Electricity flows
5
6. Terms to Know
Open circuit – there is a break
somewhere and electricity cannot flow
(maybe the switch is open)
Closed circuit – electricity can flow (the
switch is closed)
Short circuit – the electricity completes a
circuit without going through the load
Load – what is using the electricity
6
7. Schematics
Circuit diagrams, also called
schematic diagrams, provide a
graphic representation of an
electric circuit using standard
symbols.
7
8. Diagram Symbols
wire or conductor
resistor or other load
bulb V
voltmeter
battery A
ammeter
switch generator 8
18. Resistance in Series
Add up all resistors to
get total
Totalresistance will go
up because all of the
current must go through
each resistor.
19. Sample Problem #1
Draw a series circuit with two 1.5
V batteries, 3 resistors, and a
current of 0.5 A.
1. What is the total voltage of the
circuit?
2. What is the resistance of each
resistor?
20. Parallel Circuits
Has at least one point
where current divides
More than one path for
current to flow
Paths are also known as
branches
22. Parallel:
Ifyou add a resistor:
Total resistance goes
down
Total current goes up
when you add
another path
23. Removing a Light
Bulb
If you remove a light
bulb or one burns out,
the others stay on
because the circuit is
still closed.
24. Current in Parallel
Current flows into a
branching point, the
same total current must
flow out again
Current depends on
resistance in each
branch
27. Practice problem #2
Draw a parallel circuit with
two resistors (one on each
branch) and a 12 V battery.
1. What is the voltage through
each resistor?
29. Toll Booth
Explanation
Adding toll booths in series
increases resistance and
slows the current flow.
Adding toll booths in
parallel lowers resistance
and increases the current
flow.
31. In series—The voltage
is increased.
In parallel—No
change in voltage;
these batteries will
last longer!
32. One More FINAL
Thing:
Two Types of Current:
DC—Direct Current—
produced by solar cells
and chemical cells
(batteries)
Current only flows in
one direction.
33. 2 type of current:
nd
AC—Alternating Current
Current flows back and
forth (alternates)
Found in homes
Generators produce AC
current
Notas do Editor
Circuit A circuit is a path for electrons to flow through. The path is from a power sources negative terminal, through the various components and on to the positive terminal. Think of it as a circle. The paths may split off here and there but they always form a line from the negative to positive. NOTE: Negatively charged electrons in a conductor are attracted to the positive side of the power source. Simple Circuit If we break a circuit down to it's elementary blocks we get: 1) A Power Source -- eg: battery 2) A Path -- eg: a wire 3) A Load -- eg: a lamp 4) A Control -- eg: switch (Optional) 5) An indicator -- eg: Meter (Optional) Series Circuit A series circuit is one with all the loads in a row. Like links in a chain. There is only ONE path for the electricity to flow. If this circuit was a string of light bulbs, and one blew out, the remaining bulbs would turn off. There are specific properties to this circuit that will be described in another section. NOTE: The squiggly lines in the diagram are the symbol for Resistors. The parallel lines are the symbol for a battery. Parallel Circuit A parallel circuit is one that has two or more paths for the electricity to flow. In other words, the loads are parallel to each other. If the loads in this circuit were light bulbs and one blew out there is still current flowing to the others as they are still in a direct path from the negative to positive terminals of the battery. There are specific properties to a parallel circuit that will be described in another section. Combination Circuit A combination circuit is one that has a "combination" of series and parallel paths for the electricity to flow. Its properties are a synthesis of the two. In this example, the parallel section of the circuit is like a sub-circuit and actually is part of an over-all series circuit.