This document discusses different types of circuits including closed and open circuits, circuit diagrams, common circuit symbols, series and parallel circuits, and short circuits. It explains that closed circuits allow electricity to flow while open circuits do not. Series circuits have a single path for current to flow and if any part fails the entire circuit fails, while parallel circuits have multiple independent paths so if one fails the others still work. Short circuits bypass devices and drain batteries faster while risking fires from overheating wires.

1. Circuits

2. Circuits
• Closed circuit – switch closed, electricity flows

3. Open Circuit – switch open, no electricity flows

4. Circuit Diagram
• Circuit diagrams - shortcuts
to drawing a circuit
• Circuits are made up of
different parts
– wires, switches, batteries, &
resistors

5. Common Circuit Symbols
• Wire
• Battery
• Light bulb
• Resistor

6. Types of Circuits
• Series Circuits – has only one path
– Current is the same everywhere
– Voltage decreases as it passes through resistors
– If any part circuit is broken, the circuit fails
– Ex) Older Christmas lights: if one bulb doesn’t
work, the entire strand doesn’t work.

7. • Parallel Circuits – has multiple paths for flow
– The branches are all independent: If one fails, the
rest of them still work
– Voltage and current same across branches
– Ex ) Home or school - If one thing stops working,
everything else still works

8. Short Circuit
• A short circuit is a wire that bypasses a device
in a circuit
• Electricity always chooses the path of least
resistance
• Wires have virtually no resistance, so it will go
through a wire rather than a device

10. • Short circuiting a battery cause two problems:
– Battery gets drained faster
– Wire will heat up, possibly melting the insulation,
which could start a fire