Concept Summary

Batesville High School Physics

Circuit SchematicsA schematic diagram is a symbolic

representation of a circuit. A symbol represents each item in the

circuit Lines represent wires (paths for charges).

Circuit Symbols

Three Types of CircuitsSeriesParallelCompound

Series CircuitsSeries circuits have 1 path for charges

to flow.

Series CircuitsVoltage may be different across

different objects in a series circuit. Sum of the individual voltages = source

voltageCurrent is the same in all parts of a

series circuit. If one “goes out”, they all “go out”

Parallel CircuitsA parallel circuit has two or more paths

for charges to move.

Parallel CircuitsVoltage is the same across each

element in a parallel circuit.Current may vary through different

elements in a parallel circuit.Sum of the individual currents = source

current. If one “goes out”, the other “stays lit”.

Compound CircuitsA compound circuit has both series and

parallel parts.

Adding Resistance in SeriesWhen you add resistance in series:

Total resistance increases Current decreases

Equivalent Series Circuits

Rseries = R1 + R2

Adding Resistance in ParallelWhen you add resistance in parallel:

Total resistance decreases Current increases

Equivalent Parallel Circuits

Household CircuitsHousehold circuits are:

parallel circuits Typically designed to carry 15 Amperes of

current - maximum.

Overloading CircuitsSince adding resistance to a parallel

circuit causes current to increase, adding appliances to a household circuit causes current in the house wiring to increase.

This means wires must dissipate more heat energy (P = I2R).

Short CircuitsA short circuit is a very low resistance

path in a circuit.A short circuit will also cause large

amounts of current to flow in a circuit and overload the circuit.

Fuses & Circuit BreakersFuses and circuit breakers act as

automatic switches in a circuit to prevent dangerous currents from flowing.

The End