They can also be considered a resistor. This resistor activity will show that as the length of the semiconductor changes, the brightness of the bulb changes. Ohm constructed wires of many different lengths and thicknesses. Today, we simply call these devices resistors because all they do is resist the flow of current. He discovered that for each resistor, no matter what potential difference he applied, the resistance was the same.
Resistors are very important in circuits.
They are used to control current or potential difference in a circuit. Before beginning this activity, prepare the pencils. Using a utility knife, cut half of the wood away so that the lead is exposed. If you are not comfortable with cutting pencils, it is possible to purchase pencil lead. Create a complete circuit with the bulb, battery and wire.