Required Practical 4: Current / PD Characteristics

• What does a straight line passing through zero on the graph indicate for a resistor?

  Current is directly proportional to potential difference
• What type of conductor is a resistor described as?

  Ohmic conductor
• What happens to the graph if the temperature of the resistor increases?

  The graph will not have a straight line shape
• Why does the current not remain proportional to the potential difference in a filament lamp?

  Increased temperature causes resistance to increase
• What happens to the current when the potential difference is reversed in a diode?

  No current flows due to high resistance
• What is the significance of the extra resistor in the diode circuit?

  It protects the diode from high current
• What is the typical voltage range for current to flow in a diode?

  0.6 to 0.7 volts