In this activity, you will connect lamps and LEDs individually to an electrical energy source and investigate the effects of changing the amount of electrical energy supplied to them. The apparatus uses a small battery as an energy source. The amount of energy reaching the lamp or LED is controlled by a potentiometer --- a small rectangular device with a screw on one end. Turning the screw changes the energy going to the lamp or LED in the sockets. The apparatus used for these measurements is shown below.
Check the apparatus by inserting the incandescent lamp in its socket and connect the battery to the battery clips. Adjust the meter in the circuit so that it will have a range of about 0-9 Volts and it will measure voltage. If it does not, turn the screw on the potentiometer in the counterclockwise direction until the light comes on. If the lamp still does not emit light, check the connections.
If you do not have access to the electric circuit illustrated above, you can use the virtual experiment to investigate the LEDs. Try to observe a household incandescent lamp at different voltages for the first part.
