Download Current Electricity

Current Electricity Current Electricity
• when electric charges stay in one place, they are called
static electricity
• when electric charges move from one place to another, it is
called current electricity
Current Electricity New Words...
Electric Current - number of charges that are moving in a
circuit; measured in Amperes (A)
Potential Difference (Voltage) - amount of energy that the
charges will lose as they move around the circuit; measured in
Volts (V)
Resistance - ability of an object to slow down the charges as
they move around the circuit; measured in Ohms (Ω)
How does it work???
Voltage charges the electrons (e.g. battery), the current is the
number of electrons moving around the circuit, and resistance
uses up the charge on the electrons (e.g. lamp or motor) so they
return without any charge at the end of the circuit.
Current Electricity How much current do electrical devices use???
electronic calculator
0.002A
light bulb
0.833A
T.V.
4.1A
toaster
13.6A
How much electric current can humans take?
0.001A
we start to feel it
0.002A
muscles tingle
0.005A
maximum safe level
0.016A
muscles convulse, breathing affected
*let-go threshold
0.050A
usually FATAL! (heart can stop pumping)
0.200A
severe skin burns
Current Electricity REMEMBER:
Voltage will stun you, but it's the current that kills!
This is why a taser is safe (50,000V but only 0.03A).
TASER VIDEO
TASER VIDEO 2
Electric Circuits
•
for electrons to travel in an electric current, they
move in a loop called an electric circuit
•
an electric circuit must include these 4 parts:
1.
2.
3.
4.
energy source (cell, battery, etc...)
electrical device or load (lamp, motor, etc...)
connecting wires (to complete the loop)
switch (to turn the circuit on or off)
THINK:
Which of these provides the voltage?
Which provides the resistance?
Attachments
Taser video.wmv
Taser video 2.wmv