Transcript 9.1 Series and Parallel Circuits

9.1 Series and Parallel Circuits
BC Science 9:
p. 306-319
Voltage and Current in Circuits
• The voltage in a circuit must always be
consumed before returning to the source.
• The sum of the voltage lost on the loads of the
circuit will equal the total voltage of the
source.
• The current in a circuit must always be
accounted for and will never disappear or be
consumed.
– Current in a circuit is similar to water flowing
through pipes.
Series Circuits
• There is only one path for current to travel.
• Since there is only one path for the electrons in a
series circuit, the current in each part is equal.
• Current must pass through all loads in the circuit.
Series Circuits
• The voltage is shared by all loads in the circuit
and be used up before returning to the source.
• Each load in a series circuit uses a portion of the
total voltage.
• When a load or resistor is added in series, the
overall resistance of the circuit increases.
Parallel Circuits
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There are multiple paths for current to travel.
Current will split as some electrons go each way.
When the pathways re-join, so does the current.
The sum of the current in the pathways must equal
the overall current in the circuit.
Parallel Circuits
• When the electrons cycle through the circuit they
must choose only one path.
• The voltage drop at each load is equal to the
voltage supplied by the source.
• When a load or resistor is added in parallel, the
overall resistance of the circuit decreases.