Transcript SNC1D1 10.2 Current Electricity and Electric Circuits

10.2: Electricity and Electric
Circuits
Static vs. Current Electricity
• Static Electricity:
• Current Electricity:
charges build up in one
electrons on the move
location
Current Electricity
•
to operate electrical devices, you need a steady flow of
electrons.
• Current electricity is the continuous flow of electrons
in a circuit.
• The electrons flow continuously if the following
conditions are met:
1. there is a continual supply of energy
2. the electrons have a a complete path to flow through
(electric circuit)
Electric Circuits
An electric circuit must include:
1. An energy source – “energizes” the electrons, ex. battery,
photoelectric cell in calculator
2. a conducting wire (connector) – provides a path for
current to flow
3. A load which is a device that converts electrical energy to
another form of energy, ex. light bulb
 Many electric circuits also include a switch that turns the
circuit on or off by closing or opening the circuit.
Examples of Loads
Examples of
Loads
Converts
electricity to…
light bulb
light energy
fan
mechanical
energy
doorbell
sound energy
Schematic Circuit Diagrams
• engineers and designers of
electrical circuits use special
symbols that show the
components and connections
in a circuit.
• a drawing made with these
symbols is called a circuit
diagram.
Schematic Circuit Diagrams
• Follow these rules when you draw circuit
diagrams.
1. Always use a ruler to draw straight lines for
the conducting wires.
2. Make right-angle corners so that your
finished diagram is a rectangle.
Circuit Symbols
• Conductor or wire
– allows current to flow very easily from one part
of a circuit to another.
Circuit Symbols
•
Cell - supplies electrical energy
-the positive end is bigger than the
negative end.
Circuit Symbols
• 2 Cells
• Note: every time a cell is added you need to
draw another cell; a battery is a combination of
two or more cells
Circuit Symbols
• Ground
– a connection to earth
Circuit Symbols
• Switch - an on-off switch allows current to flow
only when it is in the closed (on) position
Circuit Symbols
• Lamp
– a load which converts electrical energy to
light
Circuit Symbols
• Resistor
– A resistor restricts the flow of current
Circuit Symbols
• Ammeter
– device that measures current
A
Circuit Symbols
• Voltmeter
• device that measures voltage
V
Circuit Symbols
Motor -electrical load that converts electrical
energy into movement
M
Circuit Building
• Draw the circuit diagrams for each circuit
described on the handout
– Now try building the circuit (substitute
the buzzers for the motors)