This definitions covers Key Terms within I-V Characteristics for GCSE Physics. Revise I-V Characteristics in Extra Topics for GCSE Physics with 13 exam-style questions and 11 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 6 of 12 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
📖 Key Terms
- I-V characteristic
- A graph of current (I, y-axis) against voltage (V, x-axis) that shows how a component behaves — whether it obeys Ohm's Law or not.
- Ohmic conductor
- A component where current is directly proportional to voltage at constant temperature. The I-V graph is a straight line through the origin. Resistance is constant.
- Resistance
- The opposition to current flow, measured in ohms (Ω). Calculated from R = V/I. On an I-V graph, resistance at any point = 1/gradient at that point.
- Threshold voltage
- The minimum forward voltage required for a diode to start conducting, typically about 0.6 V for silicon diodes.
- Forward bias
- When a voltage is applied to a diode in the direction that allows current to flow (above the threshold voltage).
- Reverse bias
- When a voltage is applied to a diode in the direction that prevents current flow. The diode has extremely high resistance in this direction.
- Rectification
- Converting alternating current (AC) to direct current (DC) using a diode, which only allows current through in one direction.
Practice questions for I-V Characteristics
What does an I-V characteristic graph show for a component?
Explain why the I-V graph for a filament lamp is not a straight line.
Quick recall flashcards
What is an ohmic conductor?
A component where current is directly proportional to voltage at constant temperature. The I-V graph is a straight line through the origin
What is a diode used for?
Converting AC to DC (rectification), because it only conducts in one direction