9.2 Current and Voltage in parallel circuits

• Physics
• Secondary Education
• Age 12,13

26 April 2023

Unit 9.2 Current and Voltage in parallel circuits

Content objectives

• I can measure current and voltage in series and parallel circuits.
• I can explain how adding more cells or lamps affects current and voltage in series circuits.
• I can explain how adding more cells or lamps affects current and voltage in series circuits.

What have I learned?

• Name the particles that flow inside wires when current flows.
• What happens to the speed of these particles as the current increases?
• State the unit of current.

Voltage

• Symbol: V
• measured in units called "volts" or V
• related to the electrical energy supplied to a circuit by the cell, battery, or power supply

Cells

• 1.5 V (usually)
• Battery - two or more cells connected in series
• Batteries commonly supply 6, 9, or 12 V.

Where do you usually see this?

Mains

• electrical supply that comes from a power station or generator of some kind
• most countries use: 220 V to 240 V
• some countries use: 110 or 120 V

Supply

• source of energy in a circuit
• can be a cell, battery, power supply, or the mains

Circuit diagram symbols

• Which symbol is for a battery? 
• How did you know?

A

B

C

Which symbol is for a battery?

Voltage Rating

• Voltage is also linked to the energy changed by components in a circuit.

Voltage Rating

What does the voltage rating tell me?

26 April 2023

Unit 9.2 Current and Voltage in parallel circuits

What do I call these devices?

What do I call the devices shown?

How are these devices connected in a circuit?

Ammeter -

Voltmeter -

Voltage in a SERIES circuit

Voltage in a SERIES circuit

Adding more components in a Series circuit

Adding more components in a Series circuit

Adding more components in a Series circuit

What happens to the current in a series circuit if you increase the number of cells?

1. current increases
2. current decreases

What happens to the voltage in a series circuit if you increase the number of cells?

1. Voltage increases across each component.
2. Voltage decreases in the battery.

Voltage in a PARALLEL circuit

What do you notice in these diagrams?

Adding more components in a Parallel circuit

Adding more components in a Parallel circuit

What happens to the supply voltage in a parallel circuit if you increase the number of cells?

1. supply voltage increases
2. supply voltage decreases

What happens to the voltage across each branch in a parallel circuit if you increase the number of cells?

1. voltage increases
2. voltage decreases

What happens to the current through the cell in a parallel circuit if you increase the number of cells?

1. current through the cell increases
2. current through the cell decreases

What happens to the current through each branch in a parallel circuit if you increase the number of cells?

1. current through each branch increases
2. current through each branch decreases

Practice Activity

voltage

parallel

series

current

Classwork Activity

What's next?