Download Electric Circuits

Electric Circuits
Chapter 1, Section 3
Voltage and Resistance
• Current in a circuit increases as
the voltage increases
• Current in a circuit decreases as
the resistance increases
Ohm’s Law
• The relationship between voltage, current,
and resistance
• Current = voltage/resistance
• I = V/R
• (A) = (V)/(Ω)
Circuits
• Series Circuit - has only 1 path for electric
current to follow
– If the path is broken at any point, the current
will not flow and the circuit will stop working
– The same current flows through all devices
connected to a series circuit but the
resistance increases with each device
Circuits
• Parallel Circuit – a circuit that has more
than one path for the electric current to
flow through
– current flows through every path, so if one
pathway is broken, it may not affect the others
– The current in each path can be different
depending on the devices connected to the
circuit on that path
Protecting Electric Circuits
• Circuits are “broken” when the current
becomes larger than 15A or 20A
• Fuses and Circuit Breakers
Electric Power
• Electric power – the rate at which electric
energy is turned into another form of
energy
• Measured in watts (W)
• Power = Current x Voltage
• P=IxV
• (W) = (A) x (V)
Electrical Safety
• Table 2 on pg 25 – KNOW IT!!
• Current as low as .5A (the current needed
to power a 60W light bulb) can be deadly
to the body
Lightning Safety
• Take shelter if you can see lightning or
hear thunder
• Avoid high places, open fields, metal
surfaces, water, and isolated high objects
• Lightning safety position
– Squat low on the balls of your feet with your
hands on your knees