4.2 Voltage sources (lesson 3)

• physics
• Middelbare school
• havo, vwo
• Leerjaar 2

4.2 Voltage sources

Voltage source

A battery always states what voltages it supplies.

A battery supplies electrical energy. 

The current tells you how many charged particles flow past every second.

The voltage tells you how much electrical energy each particle is carrying.

Voltage sources

Solar cell

dynamo

Cell

Battery

A special V-source

A capacitor stores electrical energy

When you let the charge out, the voltage gets reduced, until it is empty again.

A capacitor is often used to protect components against rapid voltage changes.

I and V

You can compare the transport of electrical energy to the transport of petrol.

Current = trucks

Voltage = petrol

Or a central heating

current = water, voltage = heath

Voltage

Voltage (U) is measured in Volts (V).

So a AA battery:

U = 1.5 V

Connecting batteries

If you connect batteries in series (behind each other), you can add their voltages together.

Voltages

mains voltage = 230 V

Safe voltages = voltages untill 24 V

You can convert the mains voltage with a transformer.

Study Skills 7 on page 309

Chemical voltage sources

Batteries are chemical voltage sources because the voltage is generated by chemical reactions.

In rechargeable batteries you can make this reaction go in the opposite direction (recharge the battery). 

Batteries are small-scale chemical waste.

Hw

Read 4.2 

Do. 1 till 8