Video: Watch this demo
Description: This demonstration shows that a variable inductor connected in series with a light bulb will dim as the inductance is increased.
- Large variable iron core inductor
- 150W light bulb
- SPST switch
- C clamp
- VariAC to banana plug cable
- Banana cables
- Connect the equipment as shown in the diagram.
- Clamp the switch down to the table using a C clamp.
- Set the VariAC to 60VAC
- Test that the light bulb starts off bright, and then dims when you put the iron core into the inductor.
- Turn on the VariAC.
- With the iron core inductor out, close the switch and note how bright the light is.
- Then insert the iron core into the inductor and note that the light bulb dims. This is because the higher inductance impedes the flow of the AC current.
Note: Careful when inserting the iron core into the inductor when the power is on.
If the magnetic field is strong, the iron core may get pulled out of your hand.