Principle

The Meissner oscillating circuit used in this experiment should demonstrate the principle of deattenuation of an oscillating circuit via feedback. A system consisting of an amplifier and a feedback circuit can be caused to oscillate at a specific frequency if amplification is at least large enough to compensate the loss in amplitude in the feedback circuit and the feedback voltage at the desired frequency is in-phase with the amplified voltage. This set of requisites, known as Barkhausen's Precondition for Self- Excitation, can be fulfilled by the circuit in this experiment. The feedback factor, i.e. the ratio of the number of turns on the oscillation coil to the number on the feedback coil, is 4:1. Therefore, the voltage amplification of 4 is sufficient to fulfill the precondition for the amplitude.
The precondition for phase is only fulfilled for the intrinsic frequency of the oscillating circuit because there is a phase shift between voltage and current for all other frequencies.

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

How can undamped electromagnetic oscillation be produced?

Generate an oscillating circuit of undamped electromagnetic oscillation by feedback via a transistor amplifier stage.