I-V characteristics

• Who is demonstrating the physics practical in the study material?

  1. Roots
• What is the purpose of the practical being demonstrated?

  To find the IV characteristics of components
• What type of resistor is being tested in the practical?

  100 ohm resistor
• What other components are mentioned in the practical?

  Filament lamp and diode
• Why is a variable resistor needed in the experiment?

  To adjust the resistance for testing
• What is the maximum resistance of the variable resistor used?

  1 kilo ohm
• What happens if the variable resistor's resistance is too small?

  Good results won't be obtained
• What power supply voltage is used in the experiment?

  Up to 5 volts
• What instrument is used to measure current in the circuit?

  Ammeter
• What does the milliamp shunt do?

  Makes the ammeter more sensitive
• How should the voltmeter be connected in the circuit?

  Across the component being tested
• What should the readings of current and voltage be at the start?

  Both should be positive
• What is the first current reading taken in the experiment?

  0.01 amps
• What is the potential difference at 0.01 amps?

  1 volt
• What is the maximum current reading taken in the experiment?

  0.05 amps
• How do you change the direction of current in the circuit?

  Swap the leads on the battery
• What happens to the potential difference when the current is negative?

  It also becomes negative
• What does a straight line on the IV graph indicate for a resistor?

  It is an ohmic conductor
• What does Ohm's law state?

  Voltage equals current times resistance
• What indicates that a filament lamp is a non-ohmic conductor?

  The graph is slightly curved
• Why does the resistance of a filament lamp increase with current?

  It gets hotter, causing more collisions
• What is the minimum voltage needed for the diode experiment?

  0.55 volts
• What happens to the current when the voltage across the diode is negative?

  Current is zero
• What does the sharp increase in gradient on the diode graph indicate?

  Resistance has decreased to nearly zero
• What are the steps to set up the circuit for the IV characteristics experiment?

  1. Connect the battery or power supply.
  2. Attach the variable resistor.
  3. Connect the component being tested.
  4. Insert the ammeter in series.
  5. Connect the voltmeter across the component.
• What are the differences between the IV characteristics of a resistor, filament lamp, and diode?

  • Resistor: Linear relationship, ohmic conductor.
  • Filament lamp: Non-linear, resistance increases with current.
  • Diode: Allows current in one direction, zero current for negative voltage.
• What is the significance of plotting the IV graph?

  • Visual representation of current vs. voltage.
  • Helps identify ohmic vs. non-ohmic conductors.
  • Demonstrates the relationship between current and resistance.