Description: By coupling two coils to each other a transformer is created.
Connect the primary to an AC power supply and read off the voltage of the secondary. Can be used to show a step up or step down transformer.
- 1000 turn coil
- 500 turn coil
- Variac power supply
- 2 AC volt meters
- Very Long banana cables to connect meters to coils
- VariAC to banana plug cable
- Induction C rod and L rod
- Place the two coils on the Induction C rod. Place the L rod over them and tighten the screw.
- Connect a meter to each coil. Set it to the appropriate setting (Ex: 30VAC, Left, AC).
- Connect the variac to the primary coil. Do this last so that the professor can eaisly change between coils to power.
- Note that each meter is reading the voltage of a coil.
- Place the Meters on the overhead projector.
- Turn on the Variac and slowly raise it (don’t go above 30V). Do not touch the coils when they are powered.
- Note how the voltage of the two coils responds.
If the primary has fewer turns than the secondary, you should note the secondary coil has a larger voltage. This is an example of a Step Up transformer.
If the Primary has more turns than the secondary, you should note the secondary coil has a lower voltage. This is an example of a Step Down transformer.
- A calculation of the theoretical step up or step down voltage on the secondary can be preformed using the # of turns of each coil. Note however that the coils are not 100% efficient in real life.
- Turn off the Variac, and switch over to the other coil to try the other configuration.
- When finished, turn off the Variac.