Download Symbols for Circuits

Symbols for Circuits
Series circuit
Parallel Circuit
For a series circuit:
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Req = R1 + R2 + R3
Itot = Vbattery / Req
Ibattery = I1 = I2 = I3
Vbattery = V1 + V2 + V3
Parallel Pipes…
Parallel Circuits…
Parallel Resistors…
1 / Req = 1 / R1 + 1 / R2 + 1 / R3 + ...
Series Circuits
•The current is the same in
every resistor; this current is
equal to that in the battery.
•The sum of the voltage drops
across the individual resistors is
equal to the voltage rating of
the battery.
•The overall resistance of the
collection of resistors is equal
to the sum of the individual
resistance values,
Rtot = R1 + R2 + R3 + ...
Parallel Circuits
•The voltage drop is the same
across each parallel branch.
•The sum of the current in each
individual branch is equal to
the current outside the
branches.
•The equivalent or overall
resistance of the collection of
resistors is given by the
equation 1/Req = 1/R1 + 1/R2 +
1/R3 ...
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1 / Req = 1 / R1 + 1 / R2 + 1 / R3
Itot = ΔVbattery / Req
ΔV battery = ΔV1 = ΔV2 = ΔV3
Itot = I1 + I2 + I3
• If a schematic diagram is not provided, take the time to construct one.
• When approaching a problem involving a combination circuit, take the
time to organize yourself, writing down known values and equating
them with a symbol such as Itot, I1, R3, V2, etc.
• Know and use the appropriate formula for the equivalent resistance of
series-connected and parallel-connected resistors. Use of the wrong
formula will guarantee failure!
• Transform a combination circuit into a strictly series circuit by replacing
(in your mind, but I always draw it again) the parallel section with a
single resistor having a resistance value equal to the equivalent
resistance of the parallel section.
• Use the Ohm's law equation (V = I • R) often and appropriately. Most
answers will be determined using this equation. When using it, it is
important to substitute the appropriate values into the equation. For
instance, if calculating I2, it is important to substitute the V2 and the R2
values into the equation.