The self-induction during the switch-on process with Cobra SMARTsense

Principle

The students know that a voltage is induced in a coil as long as the magnetic field encompassed by the coil changes. They are familiar with the electromagnet and therefore also know that a current-carrying coil has a magnetic field and what the strength of the magnetic field depends on. This magnetic field must first be built up after the DC circuit is closed and must be reduced after the circuit is opened. This results in a self-induction voltage in each case.

Benefits

• Particularly comprehensible and didactically prepared description of the experiment (reference to everyday life, etc.) incl. protocol questions.
• Future-oriented teaching: Integration into digital science lessons with tablets or smartphones.
• Increased motivation among students through use of the intuitive measureAPP.
• Increased media literacy.
• No additional cable connections between the modules necessary - clearer and faster set-up.
• contact safety due to puzzle-like interlocking building blocks.
• Hard gold-plated, corrosion-resistant contacts
• Double learning success: electrical circuit diagram visible on the upper side and real components on the lower side

Tasks

What effect does a coil have when closing a DC circuit?

Using a parallel circuit of two incandescent lamps, investigate the effect of a coil installed in one of the branches.

Learning Objectives

With the experiment provided, the students should recognize that a self-induction voltage is produced when the lamp is switched on, which counteracts the increase in current.