Demonstration Manual

Electricity and Magnetism

DEM63.1 - The 1 Farad "Supercap"

Objective:

- To show that current is induced in a secondary coil by rising and collapsing magnetic field in the primary, adjacent coil.

Apparatus:

• Custom network, c/w 1 Farad capacitor, lamp and
  double-throw switch for discharging or charging.


• 6 volt lantern battery

Method:

Connect the fan/motor to the red/black terminals. With the knife switch open, connect the 6 volt lantern battery (red,positive). Move the switch to the right (charge). The lamp and motor will be on, due to the charging current through them. After about 45 seconds, the lamp will be virtually out, but the motor will still operate for about another minute. Charging of the supercap is now complete.

Move the switch to the left (discharge). The stored energy in the supercap will light the lamp and spin the motor, for the samr time as for charging. Disconnect the battery to show that the energy is coming from the supercap.