Self-induction when switching a circuit on

Principle

The students know that voltage is induced in a coil as long as the magnetic field inside the coil varies. They are familiar with electromagnets and, therefore, know that a coil with a current flowing through it produces a magnetic field and they know the factors responsible for the strength of the magnetic field.
This magnetic field takes time to form when the circuit is switched on and takes time to fade away when the circuit is switched off. This causes self-induced voltage to be formed each time.
In this experiment, the students should see that the self-induced voltage formed when switching on the circuit counteracts the increase in current.

Benefits

• No additional cable connections between the building blocks needed - clear arragned and quick setup
• Contact saftey due to puzzle blocks system
• Corrosion-free gold plated contacts
• Doubled earning sucess: Electric circuit diagram on top, real components can be seen unterside

Tasks

What effect does a coil in a direct current circuit have when the circuit is closed?

Investigate the effect of a coil installed in one of the branches in a parallel circuit of two filament lamps.