# Electrical circuits

Electrical circuits

These videos will show you how to conduct classroom experiments on building, testing and fixing electrical circuits. To conduct these experiments you will need the following equipment, most of which is available from school suppliers:

• Connecting wires or crocodile leads
• Bulb holders
• Miniature light bulbs
• Battery holders
• Batteries
• Ammeter

In this circuit, the battery is the source of energy for the lightbulb, complete the circuit by connecting the errant wire to the bulb. Adding a second battery will increase the energy source and result in the bulb shining brighter.

Similarly, adding a second bulb to the circuit as in the below video will result in them dimming.

In this series circuit, the ammeter is connected to the single bulb in the circuit, measuring the voltage it is receiving from the batteries.  Adding a second bulb to the circuit decreases the voltage received by a single bulb, and as a result, the voltage indicated on the ammeter halves. By connecting the ammeter to the second bulb, it then measures the level of voltage received by both bulbs, which is equal to all of the voltage omitted by the batteries.

The video above shows a parallel circuit with three bulbs connected in parallel, each section operates as an individual circuit and therefore can operate if the other circuits are broken. The current from the battery must still operate all the bulbs. Therefore, the current from the battery must split into three smaller currents through the bulbs. Test how the current is separated throughout the parallel circuit by placing the ammeter at different terminals.