Circuits and Ohm's Law

Circuits and Ohm's Law

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Circuit Symbols

• Battery

• Bulb

• Switch

• Resistor

Types of Circuits

• Series Circuits

• Parallel circuits

Series circuits

• All elements in the circuit are in one loop

• Every electron flow through every element

• If one bulb burned out, the rest would also go out

Parallel circuits

• There are several pathways or loops through the circuit

• Electrons flow through just one of those pathways

• If one bulb burned out, the rest of the bulbs would still glow

Multiple Choice

What kind of circuit is this?

• series

• parallel

Multiple Choice

what kind of circuit is this?

• parallel

• series

• partial

• open

Multiple Choice

This is an example of a ______ circuit

• Series

• Parallel

• Open

• Partial

Multiple Choice

What is the type of circuit that stops working when one bulb goes out?

• A broken circuit
• Parallel Circuit
• Series Circuit
• A metal circuit

Multiple Choice

In a parallel circuit if one of the light bulbs burns out the rest _________.

• stop the flow of electricity

•  can still light up

•  will go out

• of the light bulbs burn out also

Ohm's Law - V=IR

• Shows the relationship between current, voltage, and resistance

• V is for VOLTAGE (volts)

• I is for CURRENT (amps)

• R is for RESISTANCE (ohms)

Voltage (V)

• Comes from the battery or another voltage source

• The "push" that moves electrons around the circuit

• Think of it like a water pump - without the pump, the water would just sit in the pipe and not move anywhere

Current (I)

• Electrons in the circuit flowing or moving around the circuit

• Measured in amps

• When electrons move faster, the current is greater

• Like the water flowing through a pipe

Resistance (R)

• Makes it harder for electrons to flow through the circuit

• Measured in Ohms

• Kind of like friction or sand that slows the water in the pipe down

Example 1

• There are 4 amps of current flowing through a circuit with 2 ohms of resistance. How much voltage did the battery provide?

Example 2

• There are 4 amps of current flowing through a circuit with a 12 volt battery. How much resistance is in the circuit?

Example 3

• How much current would flow through a circuit with 25 ohms of resistance and 100 volt battery?

Multiple Choice

What is the resistance of a lightbulb that experiences 9 Volts and 3 amps of current?

• 1/3 ohms

• 3 ohms

• 27 ohms

• 9 ohms

Multiple Choice

What is the current in a circuit with 6 ohms of resistance and a battery containing 24 Volts?

• 1/4 A

• 144 A

• 4 A

• 0.4 A

Multiple Choice

What is the voltage of a circuit with 4 ohms of resistance and 3 amps of current?

• 12 V

• 21 V

• 4/3 V

• 3/4 V