Transcript Circuits
Circuits
Series vs Parallel
Electric Circuit
Path of current flow
As electrons move through a circuit, they
transfer potential energy from the source to
the device (load)
Circuits must be a continuous path in order
for electrons to flow (closed circuit)
Any break in pathway stops electron flow
(open circuit)
Electrons flow from – to +
Schematic Diagrams
Use symbols to show circuit
Series Circuit
Loads connected end to end
Each Electrons have only one path to
travel
electron must go through each load
before returning to the source
Same amount of charge passes through
each resistor so I is same for all
I is constant
Different Resistors
Current is constant throughout
The V across each resistor will be different for
different resistors
The total of the V of the circuit will be the sum
of the V of each resistor
V = V1 + V2 + V3
The total resistance is the sum of the
resistances of each load
REQ = R1 + R2 + R3
About Series
More resistance you add, greater the total
resistance, the less current through the circuit
Series wiring is easy and doesn’t use much
wire
One load out breaks circuit and it all goes out
Total current is decreased by the addition of
loads
Parallel Circuit
Current splits to separate branches
Each electron travels through only one load
before returning to the source
Only some of the electrons go through each
path so current is split between paths
Total current is sum of currents through each
path
ITOT = I1 + I2 + I3
About Parallel
V is constant in parallel circuit
Total resistance is actually smaller than
that of the individual resistors
Requires more wiring
Don’t all go out if one does
No loss of brightness (V) across
resistors
Example
Two 100 Ω resistors are connected a) in
series and b) in parallel to a 24V
battery. What is the current through
each resistor and what is the equivalent
resistance of each circuit?