Analysis of Current-Voltage Graphs for Different Components

This page presents the current-voltage graphs for a resistor, filament lamp (bulb), and diode, along with evaluations of their characteristics.

For a resistor:

• The graph is a straight line passing through the origin.
• Potential difference is directly proportional to current, following Ohm's Law.
• Resistors are ohmic conductors with fixed resistance.

Definition: Ohm's Law states that the current through a conductor is directly proportional to the voltage across it, given that physical conditions remain constant.

For a filament lamp:

• The graph is curved, showing a non-linear relationship.
• As voltage increases, current increases at a decreasing rate.
• The lamp's resistance increases with temperature due to increased ion vibration and electron collisions.

Highlight: A filament lamp is not an ohmic conductor because its resistance changes with temperature.

For a diode:

• The graph shows current flow in only one direction.
• At low voltages, the diode has high resistance.
• Current begins to flow rapidly once a certain voltage threshold is reached.

Vocabulary: Safety resistor - A resistor used in a diode circuit to prevent excessive current flow.

Example: The diode graph shows zero current for negative voltages, illustrating its unidirectional conduction property.

Investigating Current-Voltage Graphs for Resistors, Bulbs, and Diodes

This page outlines the experimental procedure for investigating the relationship between current and potential difference in various electrical components. The standard test circuit setup is described, along with the step-by-step method for conducting the experiment.

Definition: A standard test circuit is a setup used to measure the current and voltage characteristics of electrical components.

The method involves the following steps:

1. Set up the test circuit with an ammeter in series and voltmeter in parallel with the component.
2. Adjust the variable resistor to change current and voltage.
3. Record measurements in a table.
4. Collect both positive and negative readings by switching power supply terminals.
5. Plot a graph of current against voltage.

Highlight: The experiment requires measuring and recording at least 6 different positive and negative current and voltage values for each component.

Vocabulary: Variable resistor - A resistor with an adjustable resistance value used to control current in a circuit.

Example: The circuit diagram shows the ammeter connected in series with the component being tested, while the voltmeter is connected in parallel.