This experiment serves as an introduction to the application of
transistors for amplifying alternating voltage.
The stray field produced by the transformer of the power supply
unit induces a small alternating voltage in the coil. It is so
minimal that it can not be sufficiently detected directly with the
headphones. To attain the necessary voltage amplification, the
alternating voltage is superimposed on a base voltage produced by a
voltage divider. This alternating voltage controls the collector
current periodically around the average value set by the bias
voltage. The fluctuations in the collector current produce voltage
fluctuations in the headphones, evidenced by a humming noise.
This experiment also serves as an introduction to the much
discussed "electromagnetic pollution" issue. It proves that
electrical devices produce magnetic fields in their surroundings
when being in operation.
- 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
How can electromagnetic pollution be detected?
Try to amplify the small alternating voltages induced by
alternating magnetic fields of the power supply unit in a coil so
that they can be detected on headphones.