Electric circuits require a complete conductive path for charge to flow similarly to a closed pipe system. There are two basic types of circuits: series circuits where all components are lined up in a single conductive path and current is resisted at each component, and parallel circuits where the voltage is shared across branches while current divides among paths. Circuit diagrams use symbols to represent components like resistors, batteries, and wires to depict circuit layout and connections. Voltage is measured using a voltmeter connected in parallel across a component while current is measured using an ammeter connected in series within the conductive path. Overloading can occur in parallel circuits if too much current is drawn, which is prevented using fuses or circuit breakers.

1. Electric Circuits

2. Circuit
Circuit
 complete (closed)
path along which a
charge may flow similar
to a closed set of pipes
with H2O
Battery acts as a pump

3. 2 Basic Types of Circuits
1.Series Circuits
 Everything is lined up in a row
 current goes through a single path
 current is resisted by each individual
device
What happens if one device fails?

4. 2. Parallel Circuits
 Everything is lined up separately
 Voltage is the same across each device
 Current divides among the branches

5. Circuit Diagramming
 Shorthand method of drawing circuits
• Must use symbols.
• Wires are drawn in straight lines.
• Wires meet at 90° angles.
Name Symbol Actual
Picture
Name Symbol Actual
Picture
Resistor
Open
Switch
Wire
Light
Bulb
Battery
Connecti
ng Wire
Ammeter
Crossing
Wires
Voltmeter

6. Measuring Voltage and Current
When measuring voltage, the volt meter
needs to be hooked in parallel to the
circuit.
R1
R2
R3
R4

7. Measuring Voltage and Current
When measuring amperage, the
am meter needs to be hooked in series
to the circuit.
R1 R2 R3

8. Overloading  too much current is drawn out
causing the wires to heat up
Only happens in parallel circuits
Use Fuses or Circuit Breakers
Piece of metal that
melts at a certain
current opening
the circuit
Electromagnets that
open a switch
interrupting the flow of
current